I'd like to have a sphinx (as mentioned in another thread)
It'd be a dog's body, with mini dragon wings, and dogs paws, and a jackels face, and a sort of sandstone colour. THe wings would be scaly green. It'd trot like a proud little doggy =) You would get it inside a dungeon (god realm) after a few tasks and shit. Size of a lynx
I'd like to have a chimera
It'd be a lions body with a snake for a tail, bats wings, couldn't fly as such, and a goats head on it's shoulder, just like in the drawings. It's attack would be to breath fire, doing fire dmg. You would obtain it from a boss which is considered to be the most extreme, hard-to-get to boss there is in the game (it wouldnt be part of the main story though, a bit like urgoz) When he dies it spawns out of his body, or it could be his own pet that you can charm for yourself when he dies. Size of a bear
I'd like to have a mega slug

It'd be a siege wurm the size of the character, only different skin so it resembles a slug. Despite it's size, the slugs attacks would actually do less dmg but instead they have a 20% chance of dazing for 3 secs, that'd be cool. You'd find it in a huge swamp where you're always poisoned, and theres only 1 in the area, really obscure to find if you dont have ALT held down.
Can't really think of many others i'd love to be able to play with right now. So what would you really love as a pet, (just for the fun of it).