Wylmer's Covetous Skin

Gobtober 2021: Prompt 13

A 4th-level evocation spell. Wylmer was a wily sorcerer who took up wizardry. He often used illusion spells to confound his enemies, but his favorite was devious evocation. He created this spell for it.
You focus on a creature you can see. You focus on their magically enhanced armor, if they have any, and apply that same armor effect to yourself.
Wylmer was said to be quite fond of mischievous behavior, including stealing his opponents magic. Alas, poor Wylmer was undone by his appetite. During a duel he took on his opponents abilities using similar magic. Unfortunately, he miscalculated the spell and weighed himself with their weight twenty fold. He was crushed flat like a sheet of vellum.