Humanoid Turtles! is card #18 of the 1989 trading card collection from Topps.
The cannister contained a powerful mutogen – a mutation-causing agent which enters the DNA of anyone who touches it, causing the victim to mutate into a new form. And it had the unusual property of “sensing” the gene-structure of whatever creature its host had most recently been with, causing the host to take on the physical form of that creature…
Continued on card #19: Man-Into-Ratman!