Here's another one that looks cute and innocuous at first glance. Similar to the Tribble above, Mogwais multiply out of control when exposed to water (you know, the most common substance on earth). Even worse than Tribbles, each of Gizmo's clones is a scaly demon that delights in causing chaos. If you thought Tribbles in the trunk of your car was a problem, wait until one of these guys drives off with your car or cuts your brakes or something. Given that they combine the overwhelming ability to multiply like Tribbles with an occasionally nasty temperament, they have definitely earned their place as one of the worst pets in science fiction history.

Even the most die hard cat owner will admit that for all their cuteness and cuddliness, cats can be jerks. Yet most cats aren't straight up evil like M.A.D. Cat from Inspector Gadget. Here's a life tip: Try hard to not get pets that delight in chaos and misery. Run a background check or something first and if it turns out that the pet you are interested in is the right hand animal of a criminal organization, and has served a man named Dr. Claw... yeah, maybe go ahead and pass on that one. Find a nice hedgehog or something instead.

One of the worst pets in all of science fiction history has to be the Rancor. Do you hate being woken up in the morning by your cat or dog? Try being ripped limb from limb in the morning. The thing can't be controlled without big strong chains, and probably can't even be influenced by the Force. You'd have to own a giant mansion with a dungeon and bars to keep this thing as a pet, in which case... you're probably a super villain. If I can make a suggestion, stop being a super villain. And don't get a Rancor, no (sane) person needs one.

Another good practice when searching for a pet to adopt: Make sure they aren't an evil robot in disguise. Gir is the blundering assistant of the would-be Earth conqueror Zim, and is disguised as a dog while in public. Even in his robot form he's cute enough, but are you okay with owning a pet that has no scruples about world domination and destruction? There's also the small matter of his complete lack of intelligence and general predilection for ruining your plans for the day. That said, he does enjoy waffles, so maybe it's not all bad...

Oh boy, does Snarf ever earn his place on the list of worst science fiction pets. This strange cat/lizard/small bearded man is always getting into trouble, always needing to be saved, and has an irritating habit of ending every sentence with "Snarf!" He's like a Pokemon, but without any cool powers. If you could have Snarf or a Pokemon, take the Pokemon. Or really, take anything over Snarf.

Jabba's other pet also makes the list of worst science fiction pets. Why? That stupid laugh. Do you really want this creepy little thing hanging out in your kitchen and laughing at you every time you burn your food? Laughing at you when you die in Dark Souls? Laughing at you when you drop your phone? Laughing at you when you get out of the shower, mocking your insecurities? List goes on. There is no possible way this spiteful little creature could make a good pet.

Half Life's Dr. Kleiner may have removed the most dangerous parts of his head crab buddy Lamar, but seriously... just look at that thing! Sharp spindly legs, tumorous body, covered in gore... *Shudder* Do you want that jumping on your head when your boyfriend or girlfriend comes over? Regular crabs are bad enough. Head crabs...? Just say no. In general, don't have alien parasites as pets. I don't know what else to say, except that there's probably some sort of ban on possessing them, as they're kind of the prime example of an invasive species.