Aetherstorm Roc

Flying
Whenever Aetherstorm Roc or another creature enters the battlefield under your control, you get {E} (an energy counter).
Whenever Aetherstorm Roc attacks, you may pay {EE}. If you do, put a +1/+1 counter on it and tap up to one target creature defending player controls.

Flying
Whenever this creature or another creature you control enters, you get {E} (an energy counter).
Whenever this creature attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it and tap up to one target creature defending player controls.

Modern Horizons 3 Commander

Flying
Whenever Aetherstorm Roc or another creature enters the battlefield under your control, you get {E} (an energy counter).
Whenever Aetherstorm Roc attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it and tap up to one target creature defending player controls.