I have fond memories of it... the short as I remember:
A red pencil comes in from off camera and draws a little red pair of legs.
The pencil pokes around the legs, which run around (jumping on the pencil), and then the legs run around other lines drawn by the pencil, which sag and slide around as though it were running along a telephone wire.
After various misadventures, the legs end up being chased around by a big one-eyed basketball-like spider monster. There's a change in perspective to 3D as the legs flee down a bricked corridor, when suddenly a bunch of spiders skitter across the screen and leave behind a net-like grid, which catches the legs like a net.
The legs then start sliding around in 2D along the lines to continue ducking the big spider monster.
The action intensifies, and suddenly the film melts (as though it were being shown in a projector. A title card about experiencing technical difficulty comes up for several seconds, then the spider monster lowers itself in front of the card, swings back and forth and knocks the card over, revealing the melted film. The legs are running around on the blob of melted film, still evading the monster.
Lots of breaking the fourth wall. : ) Nickelodeon aired this short often.