Choose a damage type from these choices: (lightning, fire, cold, radiant, necrotic, force).  Your elemental is the kind of elemental that that the damage type is.  The elemental is immune to all damage of the same type.  Vulnerabilities and further resistances may apply based on the type chosen(ex: ice elemental vulnerable to fire damage).  Gain 2 points in strength and constitution.  The hit dice are d12s.  The spellcasting skill is strength.  All types have poison immunity.  Elementals are unable to cast any spells not given by its race/class.  Elementals can't wear armor.  Elementals have proficiency in strength, constitution, and can only ever "speak" elemental.  Elementals can't use weapons that aren't supplied by its class/race.  Elementals can't pick a class, and its race also functions as its class.  Elementals have proficiency in unarmed attacks. Elementals aren't slowed when squeezing through a medium sized space, and can fit through a small sized area. The squeezing disadvantages only occur when squeezing through a small sized area.  Elementals have proficiency with casting their spells.  Elementals can't carry much in their forms without moving.  They can carry small objects such as keys.  Elementals have resistance to normal damage such as bludgeoning, piercing, etc.  Their hit dice are d12s.  Has a number of level 1 spell slots equal to its level.  Regains all spell slots after a short rest.  Has proficiency and advantage when talking to an elemental when not trying to intimidate.  Can drink or eat what is stored in its form as a bonus action.

As Elementals grow stronger, they become harder to damage.  Elementals have an AC Bonus of +1x, where x is equal to the character's level.

Unarmed attack damage determined by 1d8 at level 1.  1d12 at 2, 1d20 at 3, 1d20+1d4 at 4, 1d20+1d6 at 5, 1d20+1d8 at 6.  This increasing pattern continues as long as the elemental keeps leveling up.

Gain the "elemental blast" spell.

Regain a spell slot used every minute.