Two Wizard Challenge achievements deal with projectiles: Time Takes Its Toll (slow 20 with one Slow Time) and A Forceful Rebuke (reflect 8 with one Wave of Force).
It seems like getting both with the help of the same friendly demons would be pretty easy, but I can't find any that are willing to shoot me that much; gangs are either too small or fire too slowly. Where's a good place to get shot?
Best Answer
I got both of these achievements in Act II. The desert is full of wasps that shoot littler wasps, and these littler wasps count as projectiles.
Simply find a group of wasps, cast Slow Time, and stand in the center. Since each wasp fires volleys of 4, you should get the "slow 20 projectiles" in a matter of seconds. Afterwards, simply use wave of force to send them all flying for the second one.