Adapt form

You assume a different humanoid form. When you cast the spell, choose one of the following options, the effects of which last for the duration of the spell. While the spell lasts, you can end one option as an action to gain the benefits of a different one. Armour and clothing will get out of the way of changes to the body. If this spell gets used on the caster, it will last until dispelled. When transforming the first time to a form, you get to choose the appearance of your fur or skin (separately for every form).

Possible adaptations:

• Aquatic form. You adapt your body to an aquatic environment, sprouting gills and growing webbing between your proximal phalanges, and also, a big swimming tail will arise. You can breathe and see underwater and gain a swimming speed of 40 feet, and you gain tremorsense. You cannot change any appearances in this form, and all your skills stay the same while in this form.
• Feline form. You adapt your body to become feline-like. Your whole body will get covered with fur, a tail gets created, your ears and nose become feline, your nails turn into claws, and you get pads under your feet. Your unarmed strikes deal 1d6 slashing damage, and you are proficient with your unarmed strikes. You gain +1 to stealth (if barefoot), +1 dexterity and +1 wisdom while in this form, and additionally, get the special sense of darkvision.
• Snake form. Your body turns into one of a snake, it becomes 40 feet long and 1 foot wide. You lose your legs, and your arms become less strong. Your tail is heavy, flexible and very strong. Exposed skin gets shielded by a layer of scales, and you lose all hair that isn't on your face. Your organs move to where they are in a normal snake. Movement is done by locomoting over the ground, you can barely swim or climb, and you cannot jump. You grow two sharp, venomous teeth. Venoming someone will make them take an equal amount of damage as getting poisoned, and dodging the bite requires a successful DC 12 Dexterity saving throw. You gain +1 strength, +1 constitution, -3 athletics, +1 intimidation and +1 dexterity while in this form.
• Centaur form. You become a centaur, turning your bottom half into that of a horse. Two other creatures can ride on you, and you can carry up to 200 lb. Your speed is 55 feet - 1 foot per lb carrying. You gain +1 constitution, -2 dexterity and +2 strength while in this form.
• Bat form. You become a bat, your limbs become connected with wings, and your feet turn into claws where you can grab things with or hang down from something. Your flying speed is 25 feet, and you gain -1 constitution, -1 strength, blindsight and tremorsense while in this form.

The user can use this spell infinite times if the user is level 16 or higher, and if the user is level 20, the verbal and somatic components may be ignored.