What four bosses are on the Difficult Boss Battles Mount Rushmore?

Board 8

Dracula (Castlevania)
Mike Tyson (Punch-Out!)
Lou (Guitar Hero III)
Sans (Undertale)

At first I was gonna put 'Fire and Flames', but Lou is an actual boss battle, and took me many many tries on Expert

KamikazePotato posted...
I don't think Pokemon is a good fit for this list in general. Even the most difficult parts are just not that difficult. Everything is designed so that it can be reasonably beaten by an 8-year old.
....or thousands of people sending commands in chat
azuarc wasn't even home. he was playing Magic the Gathering at his buddy's store, which is extremely easy to verify