Couple things:
(1). Most cult organizations. I'm still not entirely convinced my sister doesn't have an alien parasite in her head. >3 If you are reading this Meg, I'm sorry. Just a joke. X3
(2).Anybody named Cassie or Tobias.
3). Maple and ginger oatmeal. I don't know if there actually is an instant kind.
(4). Centaurs. All the time. :3
(5). Any time anyone else in a Roleplay I'm doing has to take over a character usually belonging to somebody else, I call it "Yeerking."
(6). The 90's Johnny Quest theme. This is an inside joke regarding the back cover of the first book that'd take me an hour to explain.
(7). Anything involving slugs or alien parasites. I had to deposit a slug by hand outside from my basement two different times. And both times, I really had to resist the urge to put the slug up against my ear. XDD
(
. Visser Three was admittedly part of the personality prototype for Mar, added with Scar's sexy voice and demeanor from The Lion King and Kuja from FFIX. The Yeerk could be downright frightening when he was written by KA sometimes, even if he was a total nutjob.
(9). Red-tailed hawks almost without fail.
(10). "This is insane," , "Let's do it," "Salad shooters," (though I've never heard the word used in any other place), and many other phrases used by down-on-their-luck rebels. Actually, a couple kids against the world generally remind me of Animorphs.
So basically, a lot of things. It's too much a part of my mind. Considering my age when I read it, aspects of Animorphs formed part of many of my earliest imaginings and thoughts.