Dragon Tempest 

Enchantment
Artist:
Willian MuraiShare:
Text:
Whenever a creature with flying enters the battlefield under your control, it gains haste until end of turn.Whenever a Dragon enters the battlefield under your control, it deals X damage to any target, where X is the number of Dragons you control.
Rulings:
- 11/17/2017 The amount of damage dealt by the Dragon that entered the battlefield is based on the number of Dragons you control when the ability resolves.
- 11/17/2017 If a Dragon entering the battlefield causes Dragon Tempest’s second ability to trigger but leaves the battlefield before that ability resolves, that Dragon still deals damage.
- 11/17/2017 The two abilities aren’t mutually exclusive. If a Dragon with flying (which is most of them) enters the battlefield under your control, both abilities will trigger.
Legality:
- standard: Not legal
- future: Not legal
- frontier: Legal
- modern: Legal
- legacy: Legal
- pauper: Not legal
- vintage: Legal
- penny: Legal
- commander: Legal
- 1v1: Legal
- duel: Legal
- brawl: Not legal
- oldschool: Not legal
- historic: Not legal
- pioneer: Legal
- gladiator: Not legal
- premodern: Not legal
- historicbrawl: Not legal
- paupercommander: Not legal
- alchemy: Not legal
- explorer: Not legal
- predh: Not legal
- oathbreaker: Legal