This potion is made by using Boxing Gloves + Brain in the cauldron. This potion doesn’t have any stackable effects.
The Brain Punch Potion gives you zombie brain gloves on your hands that will turn other people into zombie if they get hit by them.
These gloves don’t have any extra special effects, they simply just turn players into zombie if you can land a hit.
This Potion is spell number #100 in the potions book.