Chibi-Mosasaurus

A tiny Mosasaurus with a level bonus

The Chibi-Mosasaurus is a miniature pet that first appeared in the Turkey Trial 6 event of ARK: Survival Evolved; the ARK Wiki says it has been part of every event since. It is available in ARK: Survival Ascended as well. Chibis are mostly cosmetic, with one practical perk that the description spells out: "Earn XP from Alpha creature kills when equipped, to increase its level and earn additional max-levels for your Survivor!"

Levelling it up

Kill certain predators with the pet equipped and it earns experience; five level-ups are possible. Each one raises the level cap of whichever survivor has it equipped at that moment by 1, for a permanent bonus of up to 5 levels. The wiki's list of creatures that give chibi XP includes the Alpha Mosasaur, Alpha Megalodon, Alpha Leedsichthys, Alpha Tusoteuthis, Alpha T-Rex and Enraged Corrupted Triceratops. It marks some as exclusive: the Alpha Water Wyvern and Alpha Dakosaurus to ASE on Steam, and the Astral Mosasaur, Alpha Palaeoctopus and Enraged Lightning Triceratops to ASA.

Equipping and carrying it

ASE puts chibis in the off-hand slot; ASA gives them a Chibi slot of their own. Once equipped, the pet appears at the survivor's front left and follows their movement and the direction they face. During a ride it sits in the survivor's lap, and nearby while they are in bed; in a Tek Sleeping Pod it still follows the survivor's position but faces upward at their right side. It weighs 0 and stacks to 1.

Chibis count as ordinary items rather than unlockable skins. On death the pet drops with the rest of the inventory, and anyone who fails to recover the death cache loses it.

Where it comes from

Besides its event history, our records name 2 loot sources: the Fishing Items (Valentine's) and Fishing Meat (Valentine's) crates. The wiki dates the pet to patch 354.4.