Kimera

Both are 90s OVAs about vampires with an... extra terrestrial twist, and a special vampire that holds the key to saving the world, or destroying it. 

-Both ova start out with Earth being struck by a pod /meteorite containing alien lifeforms; -Both involve a mysterious green haired beauty that turns out to be crucial element in determining humanity's fate; -In both of them the girl is found in the streets by some random guys because who just doesn't pick up from streets a seemingly inofensive naked chick; -Both ova are sure to provide you a good laugh, more or less intentionally because of how poorly done they are and how surrealistically hilarious they can get. The difference is that Injuu Daikessen seems like a train wreck intentionally, while Kimera is more of a bad adaption that takes itself a bit seriously. read more 

Both have Vampires, Sci-fi, sad love story. Vampire Hunter is far more powerful though. 

Both OVAs are filled with violence, blood and nudity. They also have non-hentai grotesque tentacled monsters. If you like one, you will enjoy the other.  

Both anime deal with main protagonist having romantic feelings for a powerful creature. Both Kimera and Pupa are very grotesque and contains violence, blood and gore. However Kimera has no incest. If you like one, you will enjoy the other.