This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Ginga Nagareboshi Gin
Akakabuto and his minions with their ghastly visage and brutal slaughterings of humans are meant to scare the living daylights out of the viewers. For instance, in one flashback scene a group of lumberjacks are attacked, and we see how one of the men visibly panicked tries to crawl away from the bear towards the fourth wall, only to have the bear notice him and pounce him. Given the context of being a kids show, demonic bears killing people while eerie music plays is what one would objectively call Nightmare Fuel