Literally, it means "coconut crab," a crustacean species whose habitats are in the Indian and Pacific Oceans.
However in otaku lingo, this means "extreme low sakuga quality that is too painful to watch."
The term comes from the fourth aired
episode of "Lost Universe," which was titled "Yashigani Hofuru." When this episode aired in April of 1998, many viewers complained that the quality of this episode sucked ass. It sucked so much that the anime production staff had to redo the entire episode to put it back to standard.
Many of the blame lay on numerous of factors including:
- Time constraints on getting the go-ahead for the anime to the time of airing (It was approved in January 1998, to be aired in April 1998; less than two and a half months to make the first several episodes for the series).
- Outsourcing to an inexperienced and low quality Korean animation studio SAN HO STUDIO.
- Which they did not have a key-animation director, so there was no quality check.
- When the Japanese anime staff received the genga, it was so horrible that they had to make various revisions and refinements in a hurry.
- In which the top guys at these anime studios and producers of "Lost Universe" were upset that their Japanese key animators were still doing refinements to the genga (piece animation). With the airing date looming over the horizon, the top guys scrambled the key animators to quit their refinements and do the douga process instead.
- When the key animators protested that the final result was going to horrible, the head guys didn't hear a word of it and sent the "finished" product to the douga process, which was once again outsourced to Korea.
The production staff of "Lost Universe" was plagued from lack of time and communication from the start. When episode one aired, the OP wasn't even completed yet and it actually had SD characters with signs holding up "UNDER CONSTRUCTION." Episode two and three, you can see signs that the Japanese key animators did their best in making refinements. But by episode four, all hell broke loose. Almost every scene had to be redone for the market release.
To see a comparison of before and after scenes of episode four of "Lost Universe," see here:
Ever since then, the term "Yashigani" has been used to refer to a particular anime episode (or a series) whose quality is obviously well sub-standard to be shown on TV - or just too painful to watch.
[I-know-it's-bad] Usage example:
The TV version of "Mahou Sensei Negima" pulled off several yashigani
in several episodes.