What triggered the buying of Gamestop was people on Reddit noticing that short sellers had sold 140% of the actual amount of Gamestop stock. The hedge funds not only sold stock they didn't have (Naked Short Selling, which is illegal, at least when mere mortals do it), but 40% more than exists.
And once this becomes painfully obvious to the general public, too many uncomfortable questions are going to be asked.
I think a lot of phantom shares are created in the options market. Maybe the bigs got carried away with little ole GME.
Brokerage firms were probably loaning shares to short without possession too.
This whole thing could be epic.