Potion of frailness

This potion will multiply the damage a mob or player. So a zombie will do 2 hearts of damage without any effects, with the frailness potion, the damage is multiplied by 2 so it would deal 4 hearts of damage which would really be bad. It would add a feeling of urgency with the effect.  

It can be brewed with a potion of weakness and a poisonous potato.