Continuity mistake: Season 4, episode 10 "Ben 10 vs. The Negative 10, Part 2": When the Forever King makes his announcement "Nothing will stop this little home-coming", he stands outside the Mount Rushmore base on bare soil. But in the scene where Max reviews the recording of this speech, all of a sudden we find the Forever King standing on a neatly tiled floor.Daniel4646
Plot hole: When the Corrodium Beam is shut down, there is a brief scene of the sky clearing at Mount Rushmore. But on the cliff face all four heads are seen, whereas the head of Theodore Roosevelt got crumbled in "Secrets," and it's too far forward to have been carved into the mountain face, in place (and same position) of the old head, yet again.
Grandpa Max Tennyson: Being a hero isn't about letting others know you did the right thing, it's about you knowing you did the right thing.
Ben Tennyson: What were you just doing, reading greeting cards back at the Mega Mart?
Grandpa Max Tennyson: Well... yes.