You do not have to be a vampire -- to be undead. 
House of Mystery #291 is an issue of the series House of Mystery (Volume 1) with a cover date of April, 1981.
Synopsis for I... Vampire!: "Chapter Two: Night of the Living Undead!"
Andrew Bennett learns about a vampire drug dealer named Emil Veldt while tracking the Cult of the Blood Red Moon. He takes down his shipments with the help of Deborah Dancer and Dmitri Mishkin, fighting junkies in the process. They note the similarity between these junkies and the vampires they usually face. Hunting down Veldt at a friend's house, he bursts through the window and tells the other man's family it isn't too late. They track down Veldt to his penthouse, where Bennett breaks in and waits. It's revealed that Veldt was a heroin addict, and he explodes when Bennett throws his drugs into the sunlight. Ransacking the apartment, they are able to learn more about the Blood Red Moon's mysterious Project Interior.
Appearing in I... Vampire!: "Chapter Two: Night of the Living Undead!"
Featured Characters:
Supporting Characters:
Antagonists:
- Cult of the Blood Red Moon
- Emil Veldt (Single appearance; dies)
- Mary, Queen of Blood (Flashback only)
- Vampires
Other Characters:
- Anthony Rizzo (Single appearance)
- Cain (Host)
- Donnie Rizzo (Single appearance)
- Louisa Rizzo (Single appearance)
Locations:
- House of Mystery
- New York City
- Manhattan
- The Gates of Hell
- Oyster Bay, Long Island
- Manhattan
Items:
Synopsis for "A Cardboard Hero"
Appearing in "A Cardboard Hero"
Narrator:
- Cain (Host)
Characters:
- Arthur Walsh (Dies)
- Dr. Satana
- Ellen
- Marianne
- Peter Abott
- Victor Wolff
- Vikki
Locations:
Items:
Vehicles:
Synopsis for "Cain in the House of Mystery"
Appearing in "Cain in the House of Mystery"
Narrator:
- Cain (Host)
Characters:
- Gregory the Gargoyle (Mentioned only)
- J. Clinton Dewey
Locations:
Items:
Vehicles:
Synopsis for "The Seas Run Red!"
Appearing in "The Seas Run Red!"
Narrator:
- Cain (Host)
Characters:
- Cereno (Dies)
- Conrad
- Joseph Budd (Dies)
- Kurtz (Dies)
Locations:
Items:
Vehicles:
Notes
- I... Vampire! is continued in House of Mystery #293.