Whenever one or more creatures attack you or a planeswalker you control, if Tello, Steadfast Guard is tapped, you may untap all creatures you control.
: Tello deals 1 damage to target attacking creature and 1 damage to another target creature with the same controller.
Created for Challenge # 080, based on Steadfast Guard, which I always thought had art far too awesome to be a French vanilla common. Also drawing inspiration from Reveille Squad (another Rebel), Crossbow Infantry, and the way many Mercadian goblins are 1/1 or X/1.
The first ability would have been much shorter pre-planeswalkers: it could have simply said "Whenever you're attacked". Ah well.