if my creature with double strike attacks, do I put 2 counters on beastmaster ascension (since he attacked twice) or only one (Since he is one creature)?
if my creature with double strike attacks, do I put 2 counters on beastmaster ascension (since he attacked twice) or only one (Since he is one creature)?
Only one, because it's just one creature and because it only attacked once.
Fluttershy is best pony.
but what about the double strike?
Double strike causes it to deal damage twice, but it still only attacks once. There's a big difference.
For a creature to attack, you declare it as an attacker (during, funnily enough, your declare attackers step). Once that's done, the creature has attacked. This is when any "Whenever this/a creature attacks, do stuff" abilities (like that of Beastmaster Ascension) trigger. Once that's over and done with, the defending player declares their blockers during their, well, declare blockers step. Like before, this is when any "Whenever this/a creature blocks" abilities trigger. After all that, combat damage is assigned and dealt, and any "Whenever this/a creature deals combat damage" abilities trigger.
As you can see, Beastmaster Ascension gets its counter long, long before the creature deals damage even once, let alone twice.
Fluttershy is best pony.