Have a huge wag of chewing gum (or homemade modeling clay), green and black, lying on a plate in the middle of a table on the stage. The first boy walks in, looks at the table, and comments on how gross the bug is. Other boys come in one at a time, commenting on how terrible the bug looks, that someone needs to step on it, not sure if it's dead, etc. The last boy comes in asking if anyone has seen his gum, sees the gum on the plate, and tells the other boys never mind, picks up the gum and pretends to put it in his mouth, and walks away. The other boys comment on how disgusting and sickening that was.