This article's title is conjectural and may be subject to change as new information becomes available.
YOU'RE NOT ON
Some TMNT stuff really isn't for little kids.
In the IDW continuity's Teenage Mutant Ninja Turtles/Ghostbusters 2issue 2, Michelangelo and Peter Venkman encounter an anthropomorphic rat in Zoo Amsterdam who strongly resembles Splinter. It is Mikey who accidentally bumps into the man, who first checks to make sure his wallet hasn't been stolen, and then warns Mikey not to bump into people. The man's resemblance to Splinter is so strong that seeing him immediately triggers Mikey into having an emotional breakdown stemming from having been estranged from his own father for so long. This leads Venkman to give Mikey an impromptu psychiatric evaluation at a park bench.
It is never actually indicated whether this is actually the version of Splinter in Zoo Amsterdam's dimension. It is only his strong resemblance to Splinter that causes Mikey to react.
The colors of his fur and clothes bear a greater resemblance to the 1987 TV series version of Splinter than to the grey-furred IDW version. But unlike either of those Splinters, this character is actually wearing a jacket over a white dress shirt, necktie and slacks.