Unwilling to pass up the chance to offend someone
Panel 1:
Xeno, dressed as Captain America, and Estragon, dressed as Jesus
Xeno: Changed your mind on the costume, eh?
Estragon: Yeah. I didn't want to miss out on the chance to offend people.

Panel 2:
Estragon: Check it out. Working stigmata.

Panel 3:
Estragon squirts Custer with blood from his palms, a la Spider-Man web slinging, etc.