I got one as battle loot it's untradeable I could choose to either feed it or use it on a pet but what does it do if I use it? Is it a healing potion? If I feed a pet w/ it would it just be normal food?

It gives your pet 1-3 health points but only if they're in Tiers 1-3.

I think that's the "use" option anyway, and the "feed" option would just be like any other food.

There are a few other eggs just like it that give 1-3 points in one of the other training characteristics (strength, defense, speed).

thank you!

You're welcome! And welcome to the site. :)