Many people have been anticipating an endless variety of pets. Some people have expected it meant that the pets will share the looks of the pets being mixed. For example a firezilla and a colossus might look like part colossus and part zilla. This is not the case. The child of two pets will look exactly like some existing pet in the game. I have heard of someone mixing a wraith and an aurthurus and getting a hydra. I have only seen them come out looking like one of the parents but time will tell.
When you are playing in the test realm and want to get started with pets, check with Merle Ambrose first. He'll set you on your pet quests and give you a pet of your own.
Here's a code for the fastest wizard: 2875A-3L9W7-24NLX-5LL66