Worldwide, the rental car business was worth an eye-popping $58 billion in 2015 with the industry forecast to be worth a massive $124 billion by 2021. That’s a lot of rental cars on the roads, from the cheap and cheerful small cars beloved by college students heading to spring break to the executive luxury models preferred by business travelers who know how to make an entrance.

Once those rental cars are returned to the office, the staff have to start their real work – making sure that the cars are cleaned and valeted inside and out, ready for the next client. Often this can end up being a much bigger job than you might expect; some rental cars are returned covered in mud, after being driven on back lanes in the rain, while are others are filled with trash and unwanted items left behind by the client.

And the lost property in rental cars is not limited to items that you might expect to find left behind, such as wallets, jackets, keys and increasingly often these days, phone chargers and even the phones themselves.

As the list below shows, the staff at car rental companies sometimes have to deal with some very unusual, and occasionally some very unpleasant, items left in vehicles by customers. The mind boggles as to why anyone was driving around with these things in their rental car in the first place, let alone forgetting to take them out when they returned the vehicle.

19 Hand Grenade

Most of the time, when the valet teams at car rental businesses find lost property left in the returned cars, they will either throw it straight in the bin – in the case of that soiled underwear – or make an effort to ensure it gets returned to its rightful owner. There are some weird items, however, that warrant a call to the local police – such as the hand grenade that some terrified car cleaners found in of their cars. Luckily, the grenade, which was found in a returned rental car in Atlanta, was not real, but that won’t have been much consolation to the staff who first spotted it!

18 Snake

Strangely, finding a snake in a car is not as unusual as you might think. The cold-blooded creatures seem to enjoy hiding themselves away in the nooks and crannies around warm engines, often emerging at inopportune moments – such as when the driver is going at top speed down the highway!

Snakes have also been discovered in returned rental cars, though they usually have no connection to the person who last hired the vehicle.

In fact, the poor customer may have been driving around with a snake in their engine for days, completely unaware of the presence of their unusual hitchhiker.

17 Underwear

We are now firmly in the zone of gross-out discoveries, with the revelation that cleaning staff at rental car offices frequently find items of clothing left behind in their vehicles, and have even had to deal with items of underwear – both clean and dirty.

These workers may be used to dealing with thick mud and grime when they are cleaning the outside of a returned rental car, but surely they deserve danger money for having to deal with a stranger’s used undergarments.

It’s unlikely anyone had the nerve to come back to the office to try and reclaim these particular items.

16 Prosthetic Limb

Now, this next item is a truly bizarre item for its owner to leave anywhere; after all, how on earth does someone who relies on a false leg to get around manage to do anything without their prosthetic limb? Did they get out of the car and hop away? The only explanation is that whoever rented the vehicle also owned a spare leg, and it was that false limb that they left in the car. This is definitely the kind of lost property that you would expect to be retrieved pretty quickly, and yet other lost property offices have often reported that prosthetics are left in their possession for weeks and even months.

15 Engagement Ring

There could be a tragic tale behind the driver who left an engagement ring in the rental car he had just returned to the office, or perhaps it was simply an absent-minded woman, who had returned the vehicle without realizing that there was something important missing from her ring finger. I’m sure the staff who have found engagement and wedding rings in returned cars are hoping for a happy ending – but there is always the chance that the abandoned jewelry is evidence of the heart-breaking end to a relationship or the result of an awkward and rejected proposal of marriage.

14 Suitcase Of Cash

Most people, when presented with a suitcase stuffed with cash, would immediately assume that something criminal was going on – or at least something a little unethical.

When rental car staff came across just that in the back of one of their returned vehicles, the temptation to keep for themselves what was most likely ill-gotten gains must have been very strong indeed.

It’s one thing to pocket a dollar bill that you find while cleaning a rental car, however, but quite another to make off with thousands of dollars – especially when you remember that other people are going to be looking for that cash!

13 Live Mouse In A Cage

There is only one thing worse than discovering that the last customer has left a pet mouse in a cage in their rental car – and that’s discovering that the last customer has left a pet mouse not in a cage in their vehicle!

Still, the member of staff who stumbled across this forgotten family pet must have got quite a shock.

Let’s hope Mickey (or Minnie) eventually made his or her way home back to his loving family. Although it’s debatable as to how much of a treasured pet the lost mouse was, given that its owners forgot all about him.

12 Dummy Dressed As An Old Lady

Whoever left this next weird item in their rental car when they returned it is clearly dealing with some seriously repressed issues. After all, when you think of someone dressing up as an old lady, the first person who tends to come to mind is Norman Bates in Psycho! Luckily, on this occasion, the rental car team only had to deal with a mannequin which had been dressed up as an old lady, but it must have given them quite a turn. Perhaps for a moment they even thought that the last customer had actually left their elderly mother behind…

11 Hedge Trimmer

At least this next item on the list isn’t scary or sinister – unless whoever left it behind was actually planning on using it as a weapon, of course! However, staff finding a large hedge trimmer in a recently returned rental car is pretty weird; firstly, why on earth was someone transporting something like a hedge trimmer in a rental car in the first place, and secondly, surely an item of this size is pretty difficult to forget and leave behind on the trunk. These can be very expensive items too, so let’s hope someone came back to the office to retrieve their property.

10 Stuffed Deer's Head

Imagine opening the trunk of a car, only to find a pair of eyes staring right back at you. Pretty scary, right? Well, that’s just what one rental car company employee had to cope with when a customer accidentally left a stuffed deer head on the back of their returned vehicle. Like many of the items on this list, how anyone manages to leave such a large and expensive item is a mystery, but there are also some question marks about the client’s taste in home decoration too! Hanging a stuffed deer’s head on your wall is only a legitimate form of home decoration if you have hunted the animal yourself.

9 Complete Human Skeleton

Even on Halloween, the presence of a complete – and real – human skeleton in the back of a returned rental car is something of an unpleasant and unexpected surprise for the staff.

Hopefully, this particular skeleton was the kind used to demonstrate anatomy lessons in school and not anything more sinister!

Finding a human skull staring up at you from the trunk is certainly a day at work that none of those employees would forget in a hurry, and you can bet that they would all have been curious as to whether the customer looked as though they belonged in a horror movie.

8 Pet Dog

It’s one thing to accidentally leave your pet mouse in their cage a rental car – mice are very small and pretty quiet, after all – but one customer managed to drop off their rental car at the office with their pet dog still inside! No doubt the dog’s owner felt terrible when they got home and realized what they had done, but it was probably one of the best days at work for rental car company staff, who got to spend a few hours playing with a cute pooch. That is one mistake that the dog’s embarrassed owner would never make again.

7 Scottish Piper's Hat

If you have ever been on vacation to Scotland, then the chances are that you will have seen – and heard – people playing bagpipes in the street. Buskers aren’t the only people who play this unique instrument, as they are also part of the regimental band of the Scottish Highland infantry.

Not only do these regiments play the bagpipes, and wear the traditional Scottish kilt, but they also wear some spectacularly large hats, made from ostrich feathers dyed black, called feather bonnets.

And it was one of these unusual hats which a rental car company employee found in the back of a returned car. Hopefully losing your hat isn’t a court-martial offense for soldiers…

6 50 Lightbulbs

A lot of rental car customers have accidentally left bags of shopping in the trunk of the car they have just returned – and they usually remember within a couple of hours and head back to the office to pick up their (hopefully still fresh) groceries. Forgetting that you’ve bought a pint of milk and a loaf of bread is one thing, but forgetting that you have bought fifty lightbulbs is quite another. There must have been a great deal on the lightbulbs in the first place for someone to buy fifty, so it would have been doubly annoying to leave them in your rental car.

5 Wheelchair

Rather like the lost prosthetic limb, it is pretty difficult to figure out how someone could leave a wheelchair in the trunk of a returned rental car – unless they’re faking their injury to claim disability, of course! While there are a few people who only need a wheelchair from time to time, the more expensive models tend to be used by people whose injuries or illnesses require the use of mobility aids around the clock. So how on earth did a customer “walk” away from the rental car company office if they usually rely on a wheelchair to get around?

4 Computer Printer

Maybe people who rent cars can afford to leave some of their most expensive possessions sitting about in vehicles; maybe they’re just more forgetful than the general public!

However, there does seem to be a lot of very costly goods left behind in rental cars when they get returned to the office.

Computer printers, for example, can be pretty pricey, the kind of thing that most people manage to make last for several years before they need to splash out on a replacement. Not the rental car customer who forgot to take their printer out of the trunk when they returned home from a trip.

3 Goat Droppings

Lots of car rental companies have quite strict rules about whether or not pets can travel in their vehicles, and how they should be transported.

After all, cleaning up the mess left behind by animals is usually a little more labor-intensive than cleaning up after people.

Which is why one group of rental car staff in South Africa were pretty disgusted to find animal droppings in the back seat of one of their vehicles, later identified as goat droppings. Why someone was transporting what is essentially a farm animal in the back of their car is a mystery that may never be solved…

2 Suit Of Armor

There must have been two questions running through the minds of the car rental office staff who found an entire suit of armor in the trunk of one of their returned vehicles; why and how. Why may be slightly easier to explain; perhaps the client wanted their home to have a medieval castle vibe or perhaps the armor was the costume for a play or re-enactment. The how is slightly more difficult to understand, given the size and value of a whole suit of armor. The customer would have had some explaining to do when they came back to the office.

1 Headstone

That customer’s embarrassment, however, would have been nothing compared to this next client, who had to explain to the staff at his local car rental office how on earth he had managed to leave a fully carved headstone in the trunk of the vehicle he had just returned to them. To be fair to the client, his terrible lapse of memory could probably be blamed on grief – and he would certainly be getting plenty of grief from his friends and family for losing the headstone for their dear departed in the first place. Let’s just hope his absent-mindedness didn’t end up delaying the funeral service itself.

Sources: Brainjet.com, msn.com,pettravel.com,latimes.com, autoslash.com