The "Batman & Dracula" trilogy is probably exactly what you're thinking it is: a three-part story, told throughout the '90s, in which an Elseworlds version of Batman learns that Count Dracula has come to Gotham City. While not canon to the main DC Universe by any stretch of the imagination, this arc is still noteworthy for featuring some of the Dark Knight's most brutal kills.
The first takes place in "Batman & Dracula: Red Rain." After discovering that Dracula and his vampires are responsible for a series of murders across Gotham, Batman lures them into the Batcave, where he detonates a number of bombs and destroys them — along with Wayne Manor. Batman impales Dracula on a utility pole, but not before being drained of all his blood and becoming immortal as a result.
In "Batman: Bloodstorm," Batman begins to lose his grip on his own humanity. After the Joker takes control of the surviving vampires and kills Catwoman, Batman enacts his revenge by draining Joker's blood and staking him through the heart to prevent his return as a vampire.
"Batman: Crimson Mist" then ups the ante considerably by having a fully-vampiric Batman going on a full-blown murder spree against Gotham's criminal underworld. Penguin, Riddler, Scarecrow, Poison Ivy, Killer Croc, Two-Face, and all the inmates of Arkham are brutally killed by Batman, whose orgy of death only comes to an end when, "seeking the true darkness of peace," he chooses to walk into sunlight and destroy himself. It's ... a lot.
