Made by the geniuses at Household Hacker, the slime formula combines 500ml of Polyvinyl Alcohol and 50ml of Borax solution. Basically, you pour in the Borax into the Polyvinyl Alcohol and stir like a mad chemist. According to Household Hacker:
This links the atoms and molecules together forming a molecular net that will trap all the water. This net is what allows the slime to flow slowly as opposed to flowing like normal water would.
Endless fun. [Household Hacker]