Could someone please tell me what all the pet zappers do? there are only 2 right?

Yes, there are two.

According to Wikibeta, the original Pet Zapper 'can change your active pet's color, species, gender, hunger, mood, or stats'.

The Pet Zapper Version 2 'can change your items [as far as I'm aware, into junk], minion, pet color, pet gender, hunger, mood, stats, add to your pet's Treasure Chest, or do nothing at all. However, the greatest difference between it and the original Pet Zapper is the V2's ability to change your pet into an Experiment that's otherwise unobtainable.'