Appendages (head) – The character has extra heads and/or unusual head.
The Dungeons and Dragon universe has several multi-headed characters.
Demogorgon (D&D 4th Edition – Monster Manual 2)
Ettin (D&D 4th Edition – Monster Manual 1)
Thrarak (D&D 4th Edition – Monster Manual 2)
Skull Lord (D&D 4th Edition – Monster Manual 1)
Carrion Hound – Creature Collection II. Dark Menagerie
Fen Hydra – D&D 4th Edition – Monster Manual 1
Gulguthhydra – TSR 2158 Monstrous Compendium Annual Volume 2
Hrinruuk’s Hound – Creature Collection II. Dark Menagerie
Mordant Hydra – D&D 4th Edition – Monster Manual 1
Savant Hydra – Creature Collection I
Hydra – World of Warcraft Monster Guide
Double Header (DC) seems handicapped by his freakish condition.
The Mercurians have an evil head and a good head in Space Squadron #3 (Atlas).
Spanko is a monster with two heads and the two heads argue with each other in S is for Spanko-A Frightening and Realistic Giant Monster Alphabet Book (Slave Labor Graphics).
A Moai with multiple heads in Doris Danger: Giant Monster Adventures (Slave Labor Graphics).
Why not transplant a second head to a single body?
Venture Bros-Two Headed Villains
Dan Dare meets the Two of Verath in The 2000 AD Years V1 (2015).
Jetta #6 (Standard Comics)
Jimmy Olsen (DC) fights a four-headed tiger in Superman’s Pal #101.
Kitty Pryde (Marvel) kills a two-headed mountain lion in Magik #2.
Slaine fights a three-headed monster in The Bowels of Hell – 2000 AD #1000.
Three headed brain in the jar in The New Harlem Heroes – Cyborg Death Trip – 2000 AD #936.
Two Headed Turtle in Ha Ha #22 (American Comics Group).
Gorynych – TSR 2145 Monstrous Compendium Annual Volume 1
Doubleheader – Fighting American #4 (Titan)