Thor vs. Dracula
Just under the wire for Halloween (my time), here's Thor vs. Dracula. 6 pages from Thor #332 and 7 from Thor #333.
During the early 80's Dracula seemed to just randomly pop up and fight every hero he could. He fought the Silver Surfer, Howard the Duck, the Defenders, the X-Men (twice) and others during this time period. Thor jumped on the bandwagon since the book was going through a down period between the end of Roy Thomas' run and the beginning of Simonson's.
Thor slays some of Dracula's victims who have arisen as vampires:
While this is going on Dracula has become obsessed with Sif and while Thor is doing this he feeds on her while she's asleep at the end of the issue. The next issue reveals Sif is now under Dracula's control and has developed amnesia. Her blood has also super-charged Dracula's powers. Thor discovers this when he goes to visit Dr. Strange and goes to confront them at the Opera.
Dracula flees through a hole in the roof and Thor follows.
Seriously who the hell tries to attack somebody who can fight evenly with the Hulk with rats?
Sif is back to normal and Dracula is killed by Dr. Strange along with every other vampire in his next appearance.