Kolaghan, the Storm's Fury

Mana cost: {3}{B}{R}
Type: Legendary Creature — Dragon
Power / toughness: 4 / 5
Set: Commander 2017 #176 (rare)
Price: $0.65 USD

Flying
Whenever a Dragon you control attacks, creatures you control get +1/+0 until end of turn.
Dash {3}{B}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Kolaghan, the Storm's Fury has 3 printings, first in Fate Reforged (2015). EDHREC ranks it #7,053 among Commander cards. It appears most in The Ur-Dragon decks (7,392 on EDHREC). 1 public deck on TCG runs it. It has 4 official rulings.

Legality

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

Public decks that run Kolaghan, the Storm's Fury

Draconic Domination - Commander 2017, led by The Ur-Dragon

Commanders that run Kolaghan, the Storm's Fury most

Deck counts from EDHREC.

Often played with Kolaghan, the Storm's Fury

Cards that show up in the same decks on EDHREC.

Rulings

2014-11-24: You don’t have to attack with the creature with dash unless another ability says you do.
2014-11-24: If you pay the dash cost to cast a creature spell, that card will be returned to its owner’s hand only if it’s still on the battlefield when its triggered ability resolves. If it dies or goes to another zone before then, it will stay where it is.
2014-11-24: If you choose to pay the dash cost rather than the mana cost, you’re still casting the spell. It goes on the stack and can be responded to and countered. You can cast a creature spell for its dash cost only when you otherwise could cast that creature spell. Most of the time, this means during your main phase when the stack is empty.
2014-11-24: If a creature enters the battlefield as a copy of or becomes a copy of a creature whose dash cost was paid, the copy won’t have haste and won’t be returned to its owner’s hand.