The hands can be found in the Forgotten Temple at level 75. You should have a decent amount of mana-regen from the skill tree before attempting this achievement.
At levels 25 and 50, spam re-rolls fishing for the mind control spell. If you don't get it on either attempt, then restart the run.
The hands die fast, so you need to be quick. Fortunately you don't have to mind control them both at the same time. Mind control one, and if it dies, you can still get the achievement by subsequently mind controlling the other one.