Bant's challenge

Start with this card in the challenge zone. At beginning of your upkeep put an age counter on it an roll a dice:
1/2 - Put a 1/1 creature token into challenge zone with hexproof
3/4 - put X +1/+1 counters into target creature you don't control, while X is number of age counters on this card.
4/6 - Target creature you don't control gains vigilance and flying until your next upkeep.