Availability Cascade
A normal person would say that an Availability Cascade is a "self-reinforcing process where a certain stance gains increasing prominence in public discourse, which increases its availability to people and which therefore makes them more likely to believe it and spread it further."
But really, an Availability Cascade is when a group of people join together and lie. Once enough people are repeating the same lie, it becomes "the truth" for most normies and NPCs. Further, the information doesn't have to be true, provable, or real.
Example
Some scientist in the 1950s noted that it was "really hot today." He told his scientist buddies and then they all cooked up the Global Warming scheme. Fast forward a few decades and we are so wrapped up in this horseshit, we are using electric cars. Never mind the fact that these electric cars get their charge from power plants that burn coal or oil.