Arcanist's Might

You touch a willing creature and for the duration of the spell, it's strength is increased to 18. If the creature's strength is greater than 18, then it's instead increased by 1. When the effect ends, the creature becomes extremely lethargic. It's strength score is divided by 1 plus the spell level then rounded up by and it's movement speed is halved for the next minute. The creature must also make a DC 15 + spell's level constitution saving throw, and gains one level of exhaustion on a failed save.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the creatures strength is increased by an additional 2 points for each slot level above 1st. (ie. if the creatures strength would become 18, then with a 2nd level spell slot it becomes 20.)