Blood Ooze
CREATURE 4Swelling like a bubble about to burst, this oozing thing looks like it is made entirely from blood. Its slick, crimson skin is marred only by spots that look like clots formed on the surface.
Created through the foulest of alchemical rituals, the blood ooze seeks only one thing: to increase its mass by consuming blood from the living. The blood ooze hides within the body of its victims, only bursting out to attack when another meal draws near, leaving the body a husk of its former self.
The process by which such an ooze is created involves draining the blood of at least four Medium creatures and feeding all of the collected blood to a fifth creature, along with deadly reagents designed to prevent the blood from coagulating. During this time, the host slowly dies while the blood ooze takes form, emerging 2 to 6 hours later. Blood oozes have no loyalty toward those who created them, but some creators have noted that newly formed blood oozes seem to avoid harming other members of the host creature's family.
It is not widely known that an existing blood ooze can reproduce by splitting itself in half. It undergoes this division only if it has grown so large that splitting in half would create a pair of normal-sized blood oozes, such as the one listed below.
A blood ooze can seep into a corpse's wounds, displacing its natural blood. It can burst out of the corpse as a free action.
A blood ooze can sense nearby motion through vibration and air movement.
Whenever a creature adjacent to a blood ooze takes bleed damage, the blood ooze regains an amount of Hit Points equal to the damage dealt.
The blood ooze draws forth blood from nearby creatures, causing their flesh to break open and blood to spill out which replenishes the blood ooze. Each living creature within 15 feet takes 3d6 slashing damage (DC 21 basic Fortitude save).
The blood ooze regains an amount of Hit Points equal to half the damage Siphon Vitality dealt to the single creature that took the most damage.