Charles Laughton

Charles Laughton is the face on the moon in the Never-Ending Story. Supposedly, if one enters his mouth, they enter a trippy tunnel with visuals like this and will be teleported out somewhere once reaching the end of the tunnel. This gag is a reference to the YouTube channel "HourOfPoop".

The gag first appears in Chapter 3 Part 19 while the protagonists are driving in a car, and Wallace tells the protagonists that the moon is Charles Laughton. Sure enough, this really is the case and the car goes flying into his mouth, leading through a trippy tunnel that eventually teleports the protagonists back to the dark tunnel they were in a few minutes prior.