Takahashi collaborated with Yoshio Sawai by drawing a picture of Dark Yugi for Bobobo-bo Bo-bobo, where he pops out of Bobobo's afro at one point.
Takahashi and Mike Mignola, the creator of Hellboy, also participated in an art exchange (with Takahashi drawing Hellboy with Yugi Mutou's hairdo, a Millennium Puzzle, and a duel disk and Mignola drawing Hellboy wearing a Millennium Puzzle and a Yugi T-shirt) [REF].