On the Marauder's Map level on the Playstation 2 and X-Box versions, if the player is caught by Snape for unknown reasons Snape will just continuously cough and splutter.
Throwing Dungbombs at certain characters occasionally causes them to either say dialogue belonging to other characters or that was removed from the game. For example, throwing Dungbombs at Snape causes him to start saying Sir Cadogan's dialogue. Throwing Dungbombs at Parvati Patil causes her to talk about owl racing which she won't say if you talk to her via normal means. These are not "Easter Eggs," it is in fact a glitch in the game.