An EPIC is a special pet with a very special Lore:
"Fighting together with the other four EPICS, this <epic name> helped save the Prodigy World from the Puppet Master and its goons. However, using its element, it could control <element>, it banded with others. Defeated by the Puppet Master's Army, they failed to save Prodigy. They were sent into their statue forms, and only revivable if you buy them and activate them using their code."
Here is the roster of Epics: