That's right: From June 3 to July 2, there'll be a post each day highlighting Teenage Mutant Ninja Turtles canon immigrants. Now, because TMNT canon is a little confusing, it can be hard to tell what counts as a canon immigrant and what doesn't. So for the purposes of this blog, a TMNT canon immigrant is anything (a) from the movies, cartoons, video games, toy lines, or tie-in comic series that later appeared in (b) TMNT volumes 1, 2, or 4 [because they're by the original creators] or TMNT volume 5 [because the original creators are involved, it's the new official continuity, and its goal is to use as much of the diverse TMNT lore as possible].
That action figure never got made, but the idea was reworked into Mutagen Man, which was released in 1990.
He first appeared in the 80s cartoon in an episode fittingly titled "Enter: Mutagen Man!" (1991). He was a delivery worker named Seymour Gutz who fell into a vat of mutagen and somehow survived with only his eyes, brain, and a few other pieces intact.
He later made his IDW debut in Teenage Mutant Ninja Turtles: Mutanimals #1 (February 2015), where he was an experiment that went horrible wrong. Mondo Gecko later gave him the more personal name "Seymour Gutz".