Early in the episode, Hank jokes to Karen that Chelsea's family "aren't an alien race bent on intergalactic domination." Karen responds "How do you know that, do you have proof?" This is a reference to Duchovny's previous work on The X-Files, which was largely concerned with finding evidence of alien life on Earth.
At the end of the episode when the comatose girl asks " where are my clothes" Hank covers Becca's eyes. This was improvised by David Duchovny, as he thought a daughter should not see something like that.
Highest rated episode of the series