web of existence

At the end of the hour, the caster drops to level 1. They keep all their stats, spells, and other abilities. They are then converted to a member of the species of the target of the spell. They can level up as that creature, gaining new abilities as they level. At 5th, 10th, 16th, and 20th level, for each stat the creature has that is greater than 10, the spelled wizards version of that stat is permanently increased by that amount. The gains are kept after the spell ends. Every day, the enchanted creature takes 1D20 damage for each day the spell has been active. When the spelled creature drops to 0 hit points, it regains all its hit points, the spell ends, with the bonuses remaining, and the creature used for the transformation dies.