The famous "Pig concert prop" was Rodger Waters creation, so when he left the band testicles were put on it by the remaining band members to prevent Waters from suing them for using his prop.
"They added balls to it apparently. I'm told. I never actually saw this pig but they thought that meant I couldn't sue them for stealing my ideas and designs. Anyway, whatever. So piggy apparently did that tour which I never saw."
http://www.rollingstone.com/news/story/20877304/a_pigs_tale_roger_waters_traces_the_history_of_rocks_most_famous_prop/2