User blog comment:ChaseKing/Thumper, The Jack Rabbit/@comment-26186030-20150522163003/@comment-7481207-20150523112116

Consider the fact that Amumu's ultimate (one of the largest AoEs in LoL, is listed as having a range of 550. Even if you reduce if to 1000 that is still a HUGE radius. His Q range needs to be reduced as well. Compare its slowing radius (450) to the slowing field from Karma's RQ, which has a 250 radius.

Also, both the thump rate and the total duration is listed as going up per level, so if that is unintended you may want to change that.