Thomas Lennon Guest Stars as Mxyzptlk in 'Supergirl' 100th Episode (PHOTOS)
Previously portrayed by Peter Gadiot in Season 2, the trickster is now being played by Thomas Lennon. And this time, he has a proposition for Kara: What if she could go back in time and tell Lena (Katie McGrath) the truth before Lex (Jon Cryer) did? "It's a Super Life" looks back over key moments throughout the series as Kara decides if she wants to change history in order to be friends with Lena again.
How close will Kara and William get when they investigate Lex Luthor?
Click through the gallery above for a look at Lennon's guest spot, what looks like an emotional conversation between Kara and Lena, and more.
Supergirl, Sundays, 9/8c, The CW