A term derived from the free game "Dwarf Fortress," explained on the official Wiki of the game that it is the slowing down of the game's frames per second rate as a result of having too many
cats on one screen, usually avoided by not taking more than a
single cat on your adventure. Catsplosions have also been known to be harmful to the dwarves in the gameplay if you
try to reduce the cat population.
A
small Catsplosion had occurred in Will's fortress, and when he tried to control it, the dwarves of his fortress became
sad and threw tantrums, destroying
property and causing an amusing, yet painful-to-watch chain of tantrums that inevitably led to the fortress' demise.