In this week's "Supergirl" episode, "For the Girl Who Has Everything," a parasitic alien attaches itself to Kara and puts her in a dream state that makes her think her parents are alive and well on Krypton. The episode is based on "For the Man Who Has Everything" from 1985's "Superman Annual" #11.

CBS has released a new clip (via EW) that reveals J'onn J'onzz/Martian Manhunter (David Harewood) going undercover as Kara while she's out of commission. Unfortunately for J'onn, that means dealing with Cat Grant:

CBS also released the following promo for the episode, which sets up the episode's premise, familiar to fans of Alan Moore's original story:

Supergirl 1x13 "For The Girl Who Has Everything" - Kara's friends must find a way to save her life when a parasitic alien attaches itself to her and traps her in a dream world where her family is alive and her home planet was never destroyed. Also, Alex, Hank and the DEO must fend off a Kryptonian attack while Kara is out of commission, on SUPERGIRL, Monday, February 8th on CBS.

"Supergirl" airs Mondays at 8/7c on CBS.