Clayface, the iconic Batman villain, is reportedly involved as one of the major antagonists for The Batman: Part II. As Deadline reports, while the script for Matt Reeves' sequel is still being polished, currently Clayface is set to appear in the movie.
It was also reported that Mike Flanagan, the filmmaker behind Doctor Sleep, has pitched his own concept for a spin-off Clayface movie. Whether this is involved in the DC main universe or is part of Matt Reeves' spin-off is unknown.
Nothing appears to be locked in about Clayface's appearance as yet, and were he to be a villain in The Batman: Part II, we would assume due to the gritty depiction of the character that Clayface wouldn't be as gargantuan as he is in the comics.
Do you want to see Clayface in The Batman: Part II?