Invincible's evil variants of Mark Graysons are abruptly shunted out of the episode before the climax, setting up their potential return.

It seems the latest Invincible episode "What Have I Done?" delivers on the promise made in the mid-credits scene of the previous episode.

After the Invincible War in season 3 episode 7, this week's episode upped the ante as Steven Yeun's Mark Grayson faced off against Jeffrey Dean Morgan's Conquest (among other things), and fans are saying it's a highlight of not just the season, but the show – and animation – more generally.