Vampire Killer - Castlevania: Rondo of Blood

"Vampire Killer - Castlevania: Rondo of Blood" is a high quality rip of "Vampire Killer" from Castlevania: Rondo of Blood.

Jokes
It's a melody change rip that combines the melody of "Vampire Killer" with "Megalovania" from Undertale in what appears to be a mix of Undertale and Castlevania: Rondo of Blood soundfonts.

The obvious joke here is the similarity of the words "Castlevania" and "Megalovania".