Here he is. Huge, strong, tough good at grappling, slow.
Also easy to hit. Enough bullets will bring him down. If you don't like that, give him a stunt letting him defend with Endurance.
I made most of this up whole cloth, I don't remember much from the movie.
Stay-Puft Man (Chest Deep)
High Concept: Manifestation Of Gozer
Other Aspects: Made Of Marshmallow, Much Scarier Than He Ought To Be, HUUUGE
Skills:
Superb: Might, Endurance
Great: Intimidation, Discipline
Good: Conviction, Presence
Fair: Alertness, Lore
Average: Survival, Deceit
Stunts:
Crush You (Might): Attack unarmed with Might.
Big Feet (Might): May attack a zone unarmed by taking a -2 penalty.
Powers:
Titanic Size [-4]
Living Dead [-1]
Blood Drinker [-1]
Mythic Strength [-6]
Mythic Toughness [-6]
Supernatural Recovery [-4]
The Catch (poorly-foreshadowed plot devices) [+0]
Total Refresh Cost:
-24
Refresh Total:
-16