why are you guys struggling with 怪獣 lol

Literally every native just thinks of Godzilla. Textbook nerds get so confused trying to differentiate 怪獣 from 怪物 or whatever, but actually, 怪獣 is exclusively for giant radioactive beasts. If it’s not stomping Tokyo, it’s not a 怪獣, period. Stop memorizing boring kanji lists and just watch some actual media. It's not that deep.