Dr. X was created for Teenage Mutant Mutant Ninja Turtles Vol. 3 published by Image comics. He was first written by Gary Carlson who consulted with Mirage creator Ryan Brown about a storyline. The character is often credited to Brown.
Â
When Mirage started publishing Teenage Mutant Ninja Turtles Vol. 4 the Image series was considered non canon but in the companion book Tales of the TMNT V.2 an Utrom with the name Dr. X has appeared twice. Both times he is linked to Leatherhead
