noun
egg crab
A type of crab of the genus Atergatis, named for its resemblance to a steamed bun (饅頭). Usually written in kana.
まんじゅうがには、丸くて饅頭のような形をしている。
The egg crab has a round shape like a steamed bun.
磯でまんじゅうがにを見つけた。
I found an egg crab on the rocky shore.
Compound of 饅頭 (manjū, 'steamed bun') + 蟹 (kani, 'crab'), from its bun-like shape.