Rooftop Travelers

Studs you control get X +1/+1 counters as long
as you control two or more Studs.
If Rooftop Travelers would die this turn, you
may discard a card with mana value less than or
equal to X from your hand instead.
{1}{w}: Rooftop Travelers gains first-strike or indestructible until end of turn. Activate this
ability only once each turn.