Dungeons & Dragons has had many extra worlds and modules made for it, but this might be one of the most out-there. *waits for the comments to fill up with ones that are way crazier* It's Dungeons & Dragons vs. Rick and Morty (yes, the ampersand on one side and not the other is causing my eye to twitch).
From the website:
The world’s greatest roleplaying game meets television’s most dysfunctional family! What could possibly go wrong? Coming this fall, D&D has partnered with Adult Swim to bring this boxed set blending the world of Dungeons & Dragons with the mad narcissistic genius of Rick Sanchez’s power-gaming sensibilities, and it includes everything a Dungeon Master needs to channel their inner mad scientist and run a rickrolling adventure for up to 5 players, levels 1 to 3.