“Caved!!!!(Excavated!!!!)” was a mistranslation that was used by the Japanese Touhou Project community when Keine Kamishirasawa, a were-hakutaku, gets summoned to ram her hakutaku form's horns into someone's anus. Today, it has mostly become a very ancient meme.

The joke was that Keine rams her hakutaku form's horns into someone's anus, and the Japanese slang for gay anal sex was “horu” (掘る, lit. “dig” or “excavate”). At some point in time, Nifty used to translate “horareta!!!!” (掘られた!!!!) as “caved!!!!”, instead of “excavated!!!!” or “dug!!!!”, which is why the Japanese community was stuck using a mistranslation when it still had relevance.

Now, the presumed logic behind “caved” is that one of the definitions of “cave” is that it could be used as a verb meaning “to hollow out”, but the issue is that this particular definition is relatively obscure, so most people would've interpreted “caved” as a “collapse” (cave-in) or “surrender” instead. Then again, none of this matters if you're just using English to look cool.

• Personally, the correct translation for “horaneta!!!!” (掘られた!!!!) would be “Excavated!!!!”, plus it would be easier if you know that “kussaku-ki” (掘削機) gets translated to “excavator”.
  • You can use “Dug!!!!”, but it's not as versatile. The only exception for this is localization.
• At some point, “Caved!!!!” was used as the message that appears when a post/reply was deleted in one of the Touhou Project boards on Shitaraba, like 2channel's old “Aborn” (あぼーん) feature.

• Caved!!!! on Pixiv Encyclopedia
• Caved!!!! on Niconico Encyclopedia

┌―――――――――――――――――――
｜
｜
｜　　,ﾍ,_. -─ r,ﾍ,
｜　　ヽ,ﾆ)　　　ヽﾒ<!　　　Today's Subject:
｜　　 .i. ,'ﾉノ ))) 〉　　　　　　　Practice
｜　　 .| ii;ﾟ ∀ﾟﾉ|.!　＜ﾊｱｱ･･･　ﾌｳｳ･･･
｜ |＼ ||kﾘ,_\_ﾘiつ .＼　＿Ｅ[]ヨ＿＿＿＿＿＿＿
｜ |　 |￣￣￣￣￣￣|
｜ | 　| 　Eｘcavator　|