The cosmic squish principle is the theory that one can compress several universes into one with devastating effect. While appearing much earlier in the comics, the cosmic squish was first named as such in issues of the Sensational She-Hulk when Dr. Angst created a "cosmic blowhole" of sorts to draw forth a number of encroaching realities (called encroachiverses). These encroachiverses were, essentially, failed dimensions which had been compacted into receptacles to prevent interdimensional intermingling. The idea was to establish five stable points in the universe and let the rest of our universe "squish" with the encroachiverses. The resulting destruction would leave a new universe, one which Doctor Angst could control and shape at his own whim.

Strangely, this wasn't the first or only time something like this has been put into effect in the comics. Howard the Duck's first appearance in the Marvel Universe could be best described as a result of  a "Cosmic Squish" enacted by Thog, Overlord of Sominus. Even Marvel's "Dreaded Competition" has employed such concepts which would inevitably result in some kind of... ahem... "Crisis" or another.

As silly as the storyline which named "The Cosmic Squish Principle" may seem, it is one of the most frequent and recurring phenomena in the mainstream comics.