Yume Nikki is a 2004 freeware exploration game by Kikiyama, made with RPG Maker 2003, in which the player guides Madotsuki through a series of surreal dream worlds with almost no dialogue or conventional objectives. Its numbered background tracks, including BGM 017, circulated among fans through gameplay videos, soundtrack uploads and soundboards, becoming shorthand for dreamlike, unsettling internet aesthetics. The clip remains popular with editors who want instant recognition from the game's cult following without using a longer musical excerpt.