There’s no set episode given, but CB has reported that Brian McManamon will be coming to Gotham as Basil Karlo a.k.a. Clayface. It was confirmed that the villain McManamon would be playing after speculation started when the following picture was posted on his Twitter account
— Brian McManamon (@BrianMcManamon) March 11, 2016
Clayface is one of those characters that work well in cartoons and video games, but it will be interesting to see how they show the audience his ability in the show. I know I’ve harped on this before, but Batman: The Animated Series is where I saw most villain origin stories that I was not familiar with, Clayface being one of them. The original origin from the comics has Basil using a monster suit from a horror film he was in to kill, but in the animated series he has a face paste that he uses to change his appearance for movies. The face paste alters his appearance and he becomes addicted to using it, but after he gets mixed up with the wrong people he is tossed in a vat of paste and that’s how he becomes Clayface.
Go to 4:12 to see Clayface’s origin from the cartoon