Warstorm Surge

Mana cost: {5}{R}
Type: Enchantment
Set: Avatar: The Last Airbender Eternal #38 (mythic)
Price: $1.45 USD

Whenever a creature you control enters, it deals damage equal to its power to any target.

Warstorm Surge has 17 printings, first in Magic 2012 (2011). EDHREC ranks it #736 among Commander cards. It appears most in Bello, Bard of the Brambles decks (19,419 on EDHREC). 10 public decks on TCG run it. It has 2 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: not legal
standard: not legal
brawl: legal

Public decks that run Warstorm Surge

Animated Army - Bloomburrow Commander, led by Bello, Bard of the Brambles
Draconic Rage - Forgotten Realms Commander, led by Vrondiss, Rage of Ancients
Exit from Exile - Commander Legends: Battle for Baldur's Gate, led by Faldorn, Dread Wolf Herald
Merciless Rage - Commander 2019, led by Anje Falkenrath
Nature of the Beast - Commander 2013, led by Marath, Will of the Wild
Reign of Dragons - Foundations Commander, led by Lathliss, Dragon Queen
Riveteer Rampage - New Capenna Commander, led by Henzie "Toolbox" Torre
The Ruinous Powers - Warhammer 40,000 Commander, led by Abaddon the Despoiler
Wade into Battle - Commander 2015, led by Kalemne, Disciple of Iroas
Wade into Battle - Commander Anthology Volume II, led by Kalemne, Disciple of Iroas

Commanders that run Warstorm Surge most

Deck counts from EDHREC.

Bello, Bard of the Brambles: 19,419 decks
Be'lakor, the Dark Master: 8,133 decks
Norin the Wary: 6,611 decks
Neriv, Heart of the Storm: 5,178 decks
Omnath, Locus of Rage: 5,083 decks
Atla Palani, Nest Tender: 4,782 decks
Miirym, Sentinel Wyrm: 3,833 decks
Krenko, Mob Boss: 3,656 decks

Often played with Warstorm Surge

Cards that show up in the same decks on EDHREC.

Rulings

2011-09-22: Warstorm Surge is the source of the ability, but the creature is the source of the damage. The ability couldn't target a creature with protection from red, for example. It could target a creature with protection from creatures, but all the damage would be prevented. Since damage is dealt by the creature, abilities like lifelink, deathtouch and infect are taken into account, even if the creature has left the battlefield by the time it deals damage.
2011-09-22: The creature that entered deals damage equal to its current power to the targeted permanent or player. If it's no longer on the battlefield, its last known existence on the battlefield is checked to determine its power.