What is a sybil attack? Someone care to explain? 🤓

It's when a bunch of assholes create a bunch of fake accounts to spam and subvert the network's reputation - with the goal of them gaining a large influence.

Wouldn't that cost an insane amount of money?

Yes, but remember the tidal wave of Blockstream bots/shills that flooded the web after the BCH split? There are lots of entities out there that have money to burn-there are a lot of very rich people in crypto.

Fact.