Celestial Sparks

For each pair of creatures you and a opponent control, tap the one with the lowest power.
Each creature can only be affected once. Repeat this process up to the minimum between the number of creatures you control
and the number your opponent controls. If
you control more creatures, you may tap the remaining ones. Choose a target creature and deal 1 damage to it, then repeat this effect for each creature tapped this way under your control, you may change target.