Complex sentence: With the exception of Flabber, all the monsters attempt to eat any humans who trespass in their home; however, as a running gag, they never learn their lesson about trying to go after the Beetleborgs, who always manage to outwit or clobber them.
Split into simpler sentences: With the exception of Flabber, all the monsters attempt to eat any humans who trespass in their home. As a running gag, they never learn their lesson about trying to go after the Beetleborgs who always manage to outwit or clobber them.