Complex sentence: Raphael's relationship with Donatello involves (rarely serious) threats, glares, hitting and insulting, like in "I, Monster", where he throws a rat at him to get him to stop talking.
Split into simpler sentences: Raphael's relationship with Donatello involves (rarely serious) threats, glares, hitting and insulting. Like in "I, Monster", where he throws a rat at him to get him to stop talking.