It has a few different options. If it just wants to do damage, it can attack with its claws. The 2 claw attacks do a great deal of damage. While this does not feed the Vampire Spawn, it does eliminate threats. Its other option is to grapple and then bite its victims. Grappled victims must spend their turn escaping or trying to damage the vampire to where it would want to let them go. The bite takes away the victims Max HP and heals the Vampire Spawn. So, with their regeneration and biting a grappled victim, they can heal drastically.