Chimeric

Chimeric creatures are hybrids that combine the traits of a monstrous goat and a chromatic dragon with those of a third creature.
A chimeric creature has at least three heads. The goat head sits to the right of the other heads. It has glowing amber eyes and long ochre horns. The scaly dragon head sirs to the left and has black eyes. The dragon scales of a chimeric creature may be black, blue, green, red, or white. The central head of a chimeric creature is the head of the third creature. A chimeric creature has the hindquarters of a black goat, the wings of a dragon, and the forequarters of the third creature.
Chimeric creatures can always speak High Draconic 5th Edition

Creating a Chimeric Creature

"Chimeric" is a template that can be added to any Medium, Large, or Huge Animal or Magical Beast. The creature's type changes to Magical Beast if it was not already. It uses all the base creature's statistics and traits except as noted here. Adding the chimeric template to a lion results in the most traditional form of a Chimera.
Hit Dice: All current and future Hit Dice increase to d10s. Use triple the base creature's Hit Dice or 9 Hit Dice, whichever is higher.
Speed: Same as base creature, but chimeric creatures gain wings and can fly at a speed of 40 feet.
AC: Base creature's Natural Armor improves by an amount based on the Dragon type.
Attacks and Damage: A chimeric creature retains all attacks of the base creature and also gains a Bite attack for 2d6 Piercing damage, which increases to 4d6 damage if chimeric creature had advantage on the attack roll, from its dragon head and a Horns attack for 1d12 Bludgeoning damage from its goat head which knows a target Prone on a hit if the target is at least one size smaller than the chimeric creature.
Special Attacks: A chimeric creature retains all the special attacks of the base creature and also gains a breath weapon based on its dragon variety.
Breath Weapon (Recharge 5-6): The dragon head exhales destructive energy in an area. Anyone in the area can make a Dexterity saving throw (DC = 8 + the Chimeric creature's Proficiency Bonus + the Chimeric creature's Constitution modifier.) On a failure, a creature takes 31 (7d8) damage, or half as much on a success.
If the base creature did not have Multiattack, it gains the following Multiattack option.
Multiattack: The chimeric creature makes three attacks: one with its bite, one with its horns, and one with a natural weapon of its base creature. When its breath weapon is available, it can use the breath in place of one of its attacks.
To determine the head color and breath weapon randomly, roll 1d10 and consult the table below.

1d10	Head Color	Breath Weapon	AC Bonus
1-2	Black	Line of acid1	+2
3-4	Blue	Line of lightning1	+2
5-6	Green	Cone of poison gas2	+1
7-8	Red	Cone of fire2	+3
9-10	White	Cone of cold2	+2

¹The line is always 5 feet high, 5 feet wide, and 40 feet long.
²The cone is always 20 feet long.
Special Qualities: Same as base creature.
Proficiencies: Same as base creature.
Abilities: Adjust from the base creature as follows: Strength +2, Dexterity -4, Constitution +6, Wisdom +2, Charisma +2.
Challenge Rating: 6, or same as base creature +1, whichever is higher.
Alignment: Always same as dragon component.

3.5th Edition

Creating A Chimeric Creature

"Chimeric" is a template that can be added to any Medium-size, Large, or Huge animal, beast, or vermin (referred to hereafter as the base creature). The creature's type changes to magical beast. It uses all the base creature's statistics and special abilities except as noted here. Adding the chimeric template to a lion results in a chimera. (That monster is considered to already have the chimeric template.)
Hit Dice: Increased to d10. Use the base creature's Hit Dice or 9 Hit Dice, whichever is higher.
Speed: Same as base creature, but chimeric creatures gain wings and can fly at a speed of 50 feet (poor).
AC: Base creature's natural armor bonus improves by +6.
Attacks and Damage: A chimeric creature retains all 3 the attacks of the base creature and also gains a bite attack for 2d6 points of damage from its dragon head and a butt attack for 1d8 points of damage from its goat head.
Whichever natural weapon has the highest base damage becomes its primary attack. If two natural weapons have the same base damage, the one that also delivers a special attack (such as poison) is primary. If a tie still exists, choose one of the tied attacks to be primary for that creature.
Special Attacks: A chimeric creature retains all the special attacks of the base creature and also gains a breath weapon based on its dragon variety
Breath Weapon (Su): Every 1d4 rounds, a chimeric creature's dragon head can use a breath weapon that deals 3d8 points of damage. Anyone in the area can make a Reflex save for half (DC 10 + 1/2 chimeric creature's Hit Dice + chimeric creature's Constitution modifier). Use all rules for dragon breath (see the Dragon entry), except as specified in the table below.
To determine the head color and breath weapon randomly roll 1d10 and consult the table below.

1d10	Head Color Breath Weapon
1-2	Black	Line of acid1
3-4	Blue	Line of lightning1
5-6	Green	Cone of gas2
7-8	Red	Cone of fire2
9-10	White	Cone of cold2

¹The line is always 5 feet high, 5 feet wide, and 40 feet long.
²The cone is always 20 feet long. Special Qualities: Same as base creature, plus scent.
Saves: Same base saves as base creature.
Abilities: Increased from the base creature as follows: Str +4, Dex +1, Con +4, Int +2, Wis +0, Cha +0.
Skills: A chimeric creature's three heads give it a +2 racial bonus on Listen and Spot checks.
Feats: A chimeric creature gains Multiattack as a bonus feat.
Climate/Terrain: Any land or underground.
Organization: Same as base creature.
Challenge Rating: 9 or same as base creature +1, whichever is higher.
Treasure: Standard.
Alignment: Always same as dragon component.
Advancement: Same as base creature if it originally had 9 or more Hit Dice; otherwise 10-18 (same size category 19-27 (one size category larger).