Elderspell

Target one Planeswalker you can see that 1) has half of its HP remaining or less, or 2) is suffering from at least 2 levels of exhaustion - you begin to concentrate on the Elderspell and attempt to draw the target's Planeswalker Spark into your own being. After you have successfully concentrated on this spell for one full round, at the end of your 2nd turn that this spell is active, make an Arcana check. If the roll is equal to or higher than the target's spell save DC, you rip the Spark from their being and absorb it into your own. If the roll fails, you take 10d10 psychic damage, suffer 2 levels of exhaustion, and have disadvantage on all Arcana checks made for the next 8 hours. If the spell succeeds and your character level is 16 or below, make a Constitution saving throw, taking 10d10 force damage and 10d10 psychic damage on a failed save or half as much on a successful one.