Herdchaser Dragon
About this card
Herdchaser Dragon is a creature card in Magic: The Gathering with mana value 6 (color identity: green). Printed in Dragons of Tarkir (2015). Legal in Commander, Pioneer, Modern, Legacy and Vintage. Cardmarket price: €0.12.
Herdchaser Dragon 

Megamorph
When this creature is turned face up, put a +1/+1 counter on each other Dragon creature you control.
Name in each language
Legality
Rulings
2015-02-25
Turning a face-down creature with megamorph face up and putting a +1/+1 counter on it is a special action. It doesn’t use the stack and can’t be responded to.
2015-02-25
If a face-down creature with megamorph is turned face up some other way (for example, if you manifest a card with megamorph and then pay its mana cost to turn it face up), you won’t put a +1/+1 counter on it.
2015-02-25
Megamorph is a variant of the morph ability. You can find more information on morph on cards with morph from the Khans of Tarkir set.