Ada's Exhausting Rush

Choose a willing creature that you can see within range. Until the spell ends, the target's speed is doubled, it gains a +2 bonus to AC, it has advantage on Dexterity saving throws, and it gains an additional action on each of its turns. That action can be used only to take the Attack (one weapon attack only), Dash, Disengage, Hide, or Utilize action. These effects do not stack with Haste. 

When the spell ends, the target takes 1 level of exhaustion per casting. This point of exhaustion will go away with a short or long rest. This spell can kill the beneficiary if they reach a high enough level of exhaustion. The caster can accept this penalty for the spell's recipient.