During your turn, this creature has first strike. (It deals combat damage before creatures without first strike.)
During your turn, creatures you control with +1/+1 counters on them have first strike.
As the line faltered, the thunder of hoofbeats heralded desperately needed aid.
Losing or gaining first strike after first-strike damage has been dealt won't cause a creature you control to deal combat damage twice or not deal combat damage.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.