Chrom, Prismatic Speedster

Flying, haste
Whenever a creature you control with flying
and/or haste attacks, you get a chill counter.
(Chill counters can't be gained in any other way.)

{t}: If you have at least five chill counters, add
{w}{u}{b}{r}{g}, draw a card, and remove all chill
counters. (Chill counters can't be removed in any
other way.)