Beat up a little boys pet on the Timeless Isle with ease!
All three of your pets should be lvl 25, but I think it could be done with lvl 23 or 24. I haven’t needed to try, but heck why not?:
Sunreaver Micro-Sentry - (Obtained from Isle of Thunder or the AH) You’re going to get one hit before Oondasta swaps your first pet out, so start with this guy, and use Call Lightning.
Zandalari Kneebiter and Anklerender - (Obtained from Isle of Giants by killing the Zandalari guys or your AH) Have both of these as your back line pets. When the swap happens, either one will do the job. Start with Black Claw, then use Hunting Party. Oondasta will stomp your first pet after the first time you use Hunting Party. Sometimes, not often, he misses, and you get your second run of Hunting Party, but it doesn’t matter either way. Your third pet, assuming your first little baby dino dies, is your other baby dino! Easy peasy lemon squeezy! Just use Hunting Party again, and bing, bang, boom, Oondasta will be done.
Collect your 500 Celestial Coins! Remember this is a daily battle. So if your collecting coins for a trinket or saving up for the super sick mount, that’s 3500 coins toward your goal! Woot!