Evolve

You touch a beast, plant, or monstrosity with an Intelligence of 1 to 5 that has no magical abilities such as innate spellcasting. That creature must then make a Constitution saving throw, with disadvantage if it is of the same “type” (such as if you are a mammal attempting to affect another mammal) as you and with advantage if it is radically different from you (such as if you are a mammal attempting to affect a crustacean or a plant). If the creature succeeds on its saving throw, the spell is negated.

If the creature fails on its saving throw, then over the course of the next 24 hours, it slowly “evolves” into an anthropomorphic being.

The creature’s type becomes humanoid. If the creature had four or more legs, its forelimbs become arms and hands and it walks on its hind legs. A creature with no limbs or with wings instead of forelimbs has a 50% chance of growing arms. If it doesn’t grow arms, it gains another method of manipulating objects, such as prehensile feet or tail.

A Tiny creature becomes Small and its hit die type changes to d6. A Huge creature shrinks to Large and its hit die type becomes d10 (Gargantuan creatures cannot be affected by this spell). Otherwise, the creature retains its size and hit die type. Its Intelligence increases by +8. Attributes that are 5 or lower increase by 2 each, and attributes higher than 20 become 20. If the creature previously was unaligned, its alignment becomes neutral, neutral good, or neutral evil, depending on its general disposition and how it has been treated prior to this event.

This change cannot be reversed save by casting wish.

This creature will breed true with other creatures of this type (i.e., other creatures of its original species that you cast evolve on), and has a 50% chance of being able to breed true with a creature of its original type or with a humanoid.