3You Can't Find Them
Movie monsters are masters of stealth: They either strike from the shadows, or else hide in plain sight. Cthulhu is sunk beneath the ancient seas, Freddy exists as an abstract concept in the dreamscape and the Predator could literally turn invisible. They wouldn't be great monsters if you could just look them up in the phone book to leave bags of flaming poo on their doorsteps, would they?
"Well, I'll just put this out and -- wait. What is that. No. Nooooooo!"
Likewise, it is virtually impossible to find a rat. We don't mean that in a "this would be really hard for you to do over a weekend" sense; we mean that in a "horde of trained specialists equipped with the latest technology took an entire season to find one rat" sense. A group of scientists, hoping to learn more about rats' movements, took one lone rodent to a remote island that otherwise had none. They put a tracking collar on him and spent four weeks learning his favorite spots to sleep, where he ate, the routes he used, everything.
"He's gone back to that one call girl four times."
Despite laying over three dozen traps, calling in two dogs trained exclusively for the job and digging 15 "tracking tunnels," the researchers couldn't nab one little rat. They couldn't even get close. Even worse, at some point the rat actually managed to lose or break his tracking device, so they had no idea where he was anymore. When they eventually found Rat McClane, 18 weeks later, it was on an entirely different island over a quarter of a mile away. Until then, we had no idea rats could even swim that far.
So hey, you saw a rat in your place? Good luck finding it, when all the collective forces of technology and science have tested their mettle against it and were found wanting. But no, we're sure you and your "tie a tiny lasso and try to throw it around him" approach will have no difficulty eradicating that pest.
Watch out! He's going for the box cutter!
Just one tiny problem: Even if you catch it ...
2You Can't Kill Them
This one's a no-brainer: A monster is only scary if it is somehow harder to kill than a normal person. Maybe it just preys on the defenseless, like the killers from Scream, or maybe it possesses a supernatural constitution, like literally every other, significantly cooler movie monster. Seriously, Scream, your monster was Matthew Lillard? On a scale of "one to lame," that's like eight. Eight lames.
If you haven't seen it or don't know who Lillard is, we've just spoiled it for you. That's a shame.
But wait, how does this apply to rats? They're tiny little rodents. We kill them with a spring and a bit of metal. Rats aren't invincible ... right? Oh God, please tell us that's right, next sentence ...
Ha ha, not even close, pussies! In certain ways, rats are god damn immortal. For instance, what's the most surefire way you can think of to kill a rat? Poison, right? Well, to start with, rats only eat a small amount of any new food source at first, to make sure it doesn't make them ill. That's right: They caught on. They know you're trying to kill them, and are taking measures to correct that ... mistake.
"Well, you eat one poison chocolate, and then suddenly you've eaten the whole box, right?"
On top of which, humanity is starting to come up against an entirely new strain of rat, something scientists are comfortingly calling "genetically mutated super rats," which are immune to almost every type of poison.
"We must be in a recession. This is the shittiest cyanide I've ever tasted."
Dang! You know shit is getting real when even famously stoic science starts naming their new species like comic book villains.