Overclocked Electromancer

Card text

At the beginning of combat on your turn, you may pay {E}{E}{E}. If you do, put a +1/+1 counter on this creature.

Whenever this creature attacks, double its power until end of turn.

Whenever this creature deals combat damage to a creature, if that creature was dealt excess damage this turn, you get X {E}, where X is that excess damage.