coconut crab
A large terrestrial hermit crab (Birgus latro) known for climbing coconut trees.
horribly drawn animated TV show
Only with reading ヤシガニ
Slang used in anime/manga fandom, derived from the reading ヤシガニ and the cross-reference 作画崩壊 (animation quality collapse).
See also: 作画崩壊
The coconut crab is known for cracking open and eating coconuts.
That anime's art is so bad it's being called a 'coconut crab'.
Katakana spelling is common for this animal name; usually written in kana.
Kanji spelling is rare; the word is usually written in kana.
The animal name combines 椰子 “coconut palm” and 蟹 “crab.” The animation slang sense arose from the notoriously poorly animated Lost Universe episode 「ヤシガニ屠る」 and came to denote severe animation-quality collapse.