ミツメ兎 has made the Author is Sick logo!
Sometimes this tag gets used by the authors themselves, but that is conceivably just a case of the author's Chuunibyou popping its head to cover up the embarrassment or something akin to that.
Often given as a prize to people who cannot draw the routine, although in case of an artist being serious, you should keep in mind that some just did not like the art.
※Exception #1: Occasionally, the author may have been literally sick while drawing.
※Exception #2: Seldom, when an illustrator specialising in gag pictures submits a non-gag, beautiful piece of art, that gets this tag.
Author is Sick ＜ Author on Deathbed(作者は末期) ＜ Author is Missed(作者は手遅れ) ＜ Come Clinic(病院が来い) ＜ Fetch a Clinic(病院持って来い) ＜ Let's Build a Clinic Here(ここに病院を建てよう) ＜ Run Clinic Run(病院逃げて) ＜ Modern Medicine Gives Up(現代医学の敗北)
評価タグの一覧 (includes a list of Author is Sick kind of tags)
This is Terrible, WTF, Chaos, Idiot, Author is Sick Series, Take Care There, Author is for Real
Author's Mind is Transdimensional (Inazuma Eleven)
Author is Irregular (Rockman X)
Canon is Sick(公式が病気) - when the image is true to the canon AND "the author is sick", you will see this tag often.
Pikachu(ピカチュウ) — probably it was because there are many users on pixiv who try to ruin the national image of Pokémon, but at one time, each page of the Author is Sick tag search results (that is 20 hits) had at least one hit with an illustration having this yellow beast in it. It is no more as widespread these days, but there is still a tendency to re-render Pikachu overtly. Pokémon-related images get this tag relatively often in general.
ハートキャッチプリキュア — not as much as Pikachu, but it still easily gets pixiv's attention in the manner of the tag in question. えりか様's 大きなお友達's manifestation of love occurs as well, but that is even worse, being Canon is Sick.