As you can see it has at most a 28% chance and the dmg it deals is 11 max at spawn without them using their ult to add to it. It can be increased if they take dmg but only for that round.Power: Random: 1-5,3-7,5-9,7-11
Sickle: 8-28% chance to use your power to Increase Attack Damage (=to current power value)