mutant, mutation, variation, sport -- ((biology) an organism that has characteristics resulting from chromosomal alteration)
fun, play, sport -- (verbal wit or mockery (often at another's expense but not to be taken seriously); "he became a figure of fun"; "he said it in sport")
Overview of verb sport
The verb sport has 2 senses
sport, feature, boast -- (wear or display in an ostentatious or proud manner; "she was sporting a new hat")