Here is my latest attempt, a port from Pathfinder, Vampiric Mist. I look forward to your comments.
Vampiric Mist
A cloud of crimson vapour reeking of fresh blood hangs in the air, reaching out with lashing claws.
Often mistaken for a vampire in gaseous form or an unusual type of air elemental, the vampiric mist is in fact a strange form of aberrant life. With an amorphous body that consists as much of fluid as it does of air, this creature dwells in swamps or moist underground regions where its vulnerability to heat isn’t as much of a concern.
Although somewhat intelligent, vampiric mists do not form societies. They sometimes form into small gangs, but even then they show little interest in working together. Much of a vampiric mist’s time is spent seeking prey—a pursuit that the monster often shows great creativity in accomplishing. The creatures’ propensity for taking on vague, skeletal forms of the creatures whose blood they drink only further adds to their mystique and fuels rumours that they have connections to the undead. Indeed, many vampiric mists enjoy using this common misconception to their advantage, causing foes to use foolish tactics.
Dice Average 1D20 Hit Location AP/HP
STR - - 1-20 Body -*/13
CON 3D6+6 16
SIZ 3D6 11
INT 1D6+4 7
POW 3D6+2 13
DEX 2D6+12 19
CHA 3D6 10
Combat Actions: 3 (4)
Typical Armour: None, but mist-like composition provides the Intangible feature. Magic ignores this Bonus.
Damage Modifier: - 1D4
Magic Points: 13
Movement: 14m
Strike Rank: +13
Traits: Intangible, Dark Sight to 20m, Lifesense, Vampiric Touch
Skills: Athletics 50%, Brawn 80%, Evade 70%, Perception 70%, Persistence 65%, Resilience 65%, Stealth 80%
Combat Styles: Unarmed 70%
Weapons
Type Size Reach Damage AP/HP
Claw M - 1-4 -/13
Notes:
Fire Vulnerability: The vampiric mist is vulnerable to fire, and takes double damage from this element.
Lifesense: A vampiric mist can immediately sense the presence of warm-blooded creatures in a 20 meter radius as if by scent. It can detect exposed blood within a one and a half kilometres.
Vampiric: A vampiric mist drains blood with each melee touch attack dealing 1d3 points of Constitution damage. Every time a vampiric mist damages a creature in this way, it heals 1d3 hit points. Hit points healed in excess of its maximum are gained as temporary hit points, to a maximum amount equal to its Constitution score. These temporary hit points last for 1 hour.
When a vampiric mist gorges on blood to an extent that it gains temporary hit points, it moves much more quickly. It gains a 10% increase to Resilience and Evade Skill bonuses and Movement Increases to 20 m. In addition, the vampiric mist gains an additional CA in this state.
Intangible (Mist Form): A vampiric mist’s body is composed of a semisolid red mist similar in consistency to thick foam. The vampiric mist does not have a Strength score and it cannot manipulate or wear solid objects. This form grants it the intangible Chaotic Feature from the Legend Monsters Book, and allows it to move through tiny areas with no reduction to its speed.
The creature can speak in a hissing voice.