Akroan Hoplite

Oracle Text

Whenever Akroan Hoplite attacks, it gets +X/+0 until end of turn, where X is the number of attacking creatures you control.

Card Rulings

9/15/2013 Count the number of attacking creatures you control when the ability resolves to determine the value of X.
9/15/2013 Once the ability resolves, the bonus won’t change even if the number of attacking creatures you control does.