Stense's chameleon joke

Today marks the 25th anniversary of my friendship with Stense. To celebrate, here's a joke she emailed me last week:

Did you hear about the chameleon who couldn't change colour? He had a reptile dysfunction.

I think my fondness for crap jokes has finally begun to rub off.

Incidentally, it's a little-known fact that Stense has a passion for amphibians and reptiles. Indeed, the study of amphibians and reptiles is her pet -ology.

(Do you see what I did, there?)