Create Chimaera

NOTE: Listen and discuss with the DM beforehand. This spell is complicated and takes up much time. Save it by making the decision before your session.

You attempt to merge two living beings into a single form. The creature can't be a construct or an undead, and the subjects must have at least half their maximum hitpoint remaining. The resulting creature may be 3 challenge rating higher than any one of the two. The caster can choose if the creatures keep their mental faculty. This spell allows you to mix characteristic from the living beings, you do not have to fully use the mass from both A and B. The resulting being cannot revert back once finished.

During the casting period, the caster cannot take any other action and is considered paralyzed.

Game Statistics (In referral to the two beings and the result, we will use A (leading conscious), B and C (resulting being):

1. Hit points: C may assume the averaged hit points and Hit Dice of A and B (or lower). The head of the leading consciousness (A) must remain intact. Each body part grafted may switch hp correlating to the original creature, such as a limb would switch 1/6 of the original creature's hit points. If the C dies, both original being dies. If the leading consciousness C(A) is knocked unconscious and the other creature being C(B) remained conscious, it may take over your body until you awake.

2. Features: The Intelligence, Wisdom, and Charisma scores becomes 3/4 of A unless specifically stated otherwise. C also retain all of the skill and saving throw proficiencies of both A and B. If the either A or B has the same proficiency as the other and the bonus listed in its statistics is higher than the other, use the higher creature's bonus in place of the other. C cannot use any legendary actions or lair actions of the new form unless physically capable of doing so (or that the DM agrees).

3. C retain the benefit of 3 out of 4 features from A or B class, race, or other source and can use them, provided that your new form is physically capable of doing so. C can't use any special senses A and B have (for example, darkvision) unless C's physical form can use that sense. C can only speak if the A can normally speak.

4. When A and B merge, all equipment automatically falls to the ground and all equipped none-magical items will be destroyed. The GM determines whether if C can wear any equipment, based on the C's shape and size. All magical items also become unattuned. 

The spell can be repeated once more, but if a third time is attempted, the caster and both subjects immediately take 12d6 necrotic damage and the spell fails.

Complications:

1. A and B may not be under poisoned or petrified while undergoing the ritual. If done so, the spell fails and the condition spreads to the other subject and the caster.

2. If the spell is interrupted from the 6th hour on, all participants immediately take 12d6 necrotic damage, the spell fails and both A and B becomes paralyzed.

3. The spell can be dispelled by Dispell Magic, at which all participants are unharmed.

Appearance (This is all subjective and decided by the DM):

1. All visible monstrous protrusions decrease the Charisma of C by 2.

2. The size of C depends on the amount of mass merged.

3. The appearance may be used to imitate existing beings, such as a merge between a human and a bronze dragon can be used to pretend as a Dragonborn or sorcerer.

Post-Casting:

1. Both the caster and C will suffer two points of exhaustion, one at the 6th hour and one more at the 12th hour. 

2. If either A or B is friendly to the caster, C will be friendly to the caster. If neither is friendly, C will be hostile but placed under a mind control spell. C can make a Wisdom saving throw at the end of every month for a year against the caster's spell DC + wisdom modifier. If it fails more than 6 times, C will be permanently friendly to the caster. The caster can release the compulsion at any time.

3. The spell can only be undone with a Wish spell.