O is for Octoroks
Another quite specific enemy entry...but the Octorok is just as deserving of its own placement as the classic Goomba is. In case you've been living under a ROK (HAR HAR HAR) for the last 24 years, Octoroks are one of the absolute mainstays of a terribly little-known game series called umm...the...Legend of...Zelda or something? In fact, there's only one Zelda game that HASN'T had Octoroks in it...I'll give you a cookie if you can name which one it is...(NO FUCKIN' CHEATING, ASS!)
Anyway, Octoroks vary a little bit between entries in the series. They started off as land-dwelling octopus-like critters that fire rocks outta their snouts, but later became more water-based such as in Ocarina of Time and Wind Waker, where they just kinda...waited around for you to get close and then shot at you from time to time. Definitely a little bit lame compared to their more mobile counterparts from the earlier games and those with top-down perspectives. They also often come in two varieties (well, in the more classic games anyway)...a blue and a red type, where the blue Octoroks are a bit stronger and maybe a little quicker as well.
Octoroks serve as the classic underling from the Zelda series that is really the first enemy I think of when I hear "Zelda", which means you KNOW it has to be fuckin' important!
P is for Paranormal entities
This is a much more broad category, as it encompasses numerous types of baddies...but mainly I'm talking about spirits, ghosts, poltergeists and the like.
The first thing about these assholes is that there's usually a damn trick to getting rid of them. Attacking a paranormal bad guy usually means that your fist or projectile is gonna go right through the bastards, and there are numerous games where you just have to avoid them. Or they might just be completely invincible to conventional attacks, such as the Boos from Super Mario Bros. 3 and Super Mario World. The other bad thing about these dorks is that they can often fly, much like goddamn birds...this means they're usually way more mobile than you would like them to be. Couple that with their potential invincibility and you have a real fuckin' issue!
They also come in a ridiculous array of types...and they can usually phase in and out of existence, making it tough to even track these jerks. Take the Covern from Super Metroid for example, which constantly tries to phase in on Samus as you make your way through the powerless Wrecked Ship...or even the ghosts from the second level of Super Ghouls N' Ghosts, which appear in the mist and relentlessly attack you in large numbers! And don't even get me started on Specters, Ghouls, Zombies and Geists from goddamned Final Fantasy 1...constantly paralyzing your fuckin' characters. What a bunch of dicks.
Paranormal enemies often are simply roadblocks that you need to get around, or slash your way through before they manage to fill up the screen again. In most cases they act as asshole obstacles...ever since those damn Boos from Mario 3...
Oh, and I guess they can be creepy sometimes as well. Only if you're a damn sissy though.