The game you're referring to, Half-Elf Tentacle Assault , was an "adult" (hentai) homebrew title developed by a Japanese circle called around 2008. Yahoo Finance

Nintendo DS developed by Team DSX and published by Label Rouge in 2008-08-16. Universal Videogames List

If you have a more specific goal in mind, such as modding the game with a character that has tentacle abilities or finding a community that discusses such topics, I can offer more targeted advice.

For the uninitiated, ROM hacks are modified versions of existing games, often created by fans using specialized software. In the case of Half-Elf Tentacleault DS ROM Golkes, this hack takes the original Tentacleault game and turns it on its head. By exploiting the game's code, the creators of this ROM hack have introduced a range of new features, characters, and gameplay mechanics that breathe fresh life into the classic title.