Numa

Like a bottomless swamp, once you fall in, there's no getting out. Originally otaku slang for getting deeply hooked on a specific hobby or piece of content. The go-to expressions are "numa ni hamaru" (to fall into the swamp), "numa-ochi" (the moment you fell in), and "numa-ru" (to get swamped). It's mostly used positively — people happily declare their obsessions. Cosmetics numa, gaming numa, idol numa — the object of obsession can be anything. There's also "numa-raseru" (to drag someone into the swamp with you), meaning to make someone completely infatuated with you.