Tyrantrum

Tyrantrum is a Rock/Dragon-type Fossil Pokémon introduced in Generation VI (Kalos), evolving from Tyrunt and revived from the Jaw Fossil. Based on Tyrannosaurus rex, it is depicted as an apex predator that ruled the prehistoric world with its enormous, powerful jaws capable of crushing through nearly anything. Lore suggests its dominance went unchallenged in ancient times largely because of the protective feathers around its head and the immense strength of its bite, though its temperament made it difficult to control.

The Japanese name ガチゴラス (Gachigoras) appears to combine 'gachi' (ガチ, a slang intensifier meaning 'serious,' 'hardcore,' or possibly evoking 'gachin,' an onomatopoeia for a hard chomping/biting sound) with 'goras,' an ending evocative of the suffix used in kaiju and dinosaur-style names (as in Godzilla/Gojira). The English name 'Tyrantrum' blends 'tyrant' (reflecting its status as king of the ancient world) with 'Tyrannosaurus,' the dinosaur it is based on, possibly also evoking 'tantrum' for its fierce temperament.