Katara, the Fearless 
Legendary Creature — Human Warrior Ally
If a triggered ability of an Ally you control triggers, that ability triggers an additional time.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyNOT LEGALvintageNOT LEGALcommanderNOT LEGAL