The kinetic energy goes up by the velocity squared but then any damage done by the impact would be a function of the impulse and the cross sectional area of the impact. I certainly wouldn't like to get hit by this, but it is probably less lethal than those rubber rounds they use in crowd control.

edit - Boxer Rocky Marciano's punch was measured at 1028 joules, which is supposedly a greater kinetic energy than an armour piercing bullet. Direct kinetic energy comparisons are not as useful as you might think.