Reno 911's Thomas Lennon is Mxyzptlk For Supergirl's 100th Episode -- Here's The Details

Fifth dimensional imp Mxyzptlk (Mr. Mxyzptlk if you're nasty) returns to Supergirl later this month for the show's hundredth episode -- but with a twist. Well, actually, a couple of twists, but the most obvious one is that the post-Crisis version of Mxy no longer looks like the hunky Peter Gadiot, who tried to get Kara to marry him back in season two, but instead like Thomas Lennon, best known for his role on Reno 911. The episode will be a riff on "It's a Wonderful Life," which is kind of what Arrow did with its hundredth episode as well, although this time it will be a bit more overt, as Mxyzptlk offers Kara a chance to travel back in time and right one of the biggest wrongs in her life.

Unsurprisingly, the episode will be pretty Luthor-centric, with both Lex and Lena playing a key role. The question at the core of the episode: what would have played out differently if Kara had told Lena on her own that she was Supergirl, rather than being "outed" by Lex?

That regret has been one that has driven the season so far; at the end of last year, a dying Lex revealed Kara's secret to a stunned Lena, and the rage and humiliation she felt from being lied to by her best friend has driven a wedge between her and Kara. While Kara hopes to fix things, Lena keeps making sweeping declarations about how she has now "seen who you really are" and dismissing the idea of reconciliation outright. Whether Kara seeing a possible past where she moved before Lex did will make that process better or worse is anybody's guess.

You can check out the official synopsis below.

THOMAS LENNON ("RENO 911") GUEST STARS IN SUPERGIRL'S 100TH EPISODE – Mxyzptlk (guest star Thomas Lennon) returns with a proposition for Kara (Melissa Benoist) – what if she could go back in time and tell Lena (Katie McGrath) her secret before Lex did, would things turn out different? Looking back over key moments throughout the series, Kara must decide if she wants to change history to become friends with Lena again. Familiar faces return in this special episode. Jesse Warn directed the episode with story by Robert Rovner & Jessica Queller and teleplay by Derek Simon & Nicki Holcomb.

Supergirl airs on Sunday nights at 9 p.m. ET/PT on The CW, following episodes of Batwoman. "It's a Super Life" will debut on February 23.