A number of other physical effects 'gags' were also used on the film. When Genius (Ron Howard) and Mike are first observing the goo expand out of the glass, we do not see the bottom of the glass. Most likely, the goo-like substance was fed up through the open bottom of the glass, possibly with a tube. This same method was used in reverse in a scene at the park, where Genius attempts to make another batch of goo, that shrinks into nothingness.
Physical Effects were also required to move around the giant torso simulating Merrie dancing while clutching Horsey to her bosom. Most likely, the torso was on a rocking platform.
Wire-work was also used for a couple other scenes. For the last two images, a red line has been drawn to show where the wires are. As Genius tries to make more goo, a strange, peach-colored thing emerges from a beaker, and descends into the nearby sink. This was achieved by having the creation slide down the wire into the sink's drain.
At the end of the film, as Fred tries to impale Mike with a metal flagpole, the over-sized prop had it's guide wire anchored into part of the ground, and elevated somewhere off-camera. On cue, the hollow pole was released down the guide wire, and given the angle and weight, caused it to impact and allow some of the Earth in the town square to react as if Fred had thrown the 'spear.'