The pet is obtained from the new chests in store right now. The pet is a 'jackpot reward', so has about the same odds of dropping as 4k plat and 2mill gold lmao. I believe it is the hatchlings that drop (pet tokens for dragons) and you can breed them like normal pets in shop. What makes them OP is that they add a ridiculous amount to each stat and a bunch to crit abilities (when maxed). Also have a magic damage AoE DoI skill that also does DoT.. from what I hear, it's a really good skill.