To answer your question, about how many Transformers there are with vampiric tendencies, I would have to say I know of at least four, though there may be more. The four I do know of are 1.) Dead End from the Transformers movie line of figures. Dead End is a creepy Decepticon who transforms into a red sports car, (not to be confused with the G1 Decepticon also known as Dead End, and also transforms into a red sports car), but the main difference is the G1 Dead End was part of a group of five Decepticons known as Stunticons who all merged together to form a giant robot, Menasor where as the Transformers movie Dead End was just another Decepticon. He is creepy because allthough he can transform to a robot and walk on two legs, he prefers to sneak around on all fours and sneak up on fellow Decepticons as well as unsuspecting auto-bots and drain them of energy when they least expect it. Most of his fellow Decepticons are creeped out by him and avoid him at all costs. The other three Transformers are G1 Decepticons. There is RatBat - one of Soundwave's Cassette minions who transforms from an audio cassette to a purple colored Bat, and Mindwipe - a Decepticon HeadMaster who transforms from a brown and black colored robot to a giant bat with hypnotic eyes that override a robot's or even a human's will power and can force them to do his will - his human component is known as Vorath and transforms into MindWipe's head module in robot mode. The third G1 Decepticon with vampiric tendencies is known as BombBurst - he is a Pretender - his outershell resembles a huge grey vampire like monster that hides his robot mode inside the shell. BombBurst's outer shell splits apart and his robot mode emerges from within and transforms into a blue and grey "hover-jet" type vehicle with his laser rifles mounted on the side. BombBurst by far acts the most like a vampire, especially when he is inside his Pretender Shell, he kind of "loses" himself within his protective and monstrous looking outershell and "vamps" out on the closest AutoBot he can find. He sinks his fangs into an AutoBots fuel line and gorges himself until either the AutoBot is out of energy or he is distracted by yet another "tasty" victim or an all out AutoBot counter offensive to drive him away. BombBurst on the battlefield reminds me of Dracula, when he is "out on the town" so to speak. He is probably one of the most interesting Decepticon Transformers of the G1 era, besides maybe his fellow Decepticon Pretender, SkullGrin. Who acts more like Frankinstein than a Vampire by ANY stretch of the imagination.