Consuming it have a chance to restore to maximum health, but also has a chance to enter the dying status, so be careful!

Obtainment method: Use Small Glass Bottle on Void Antlered Deer during their milking period.

The Void Milk has will either restore the player's health points to full, or immediately kill them. The chances are not disclosed in game, though it's most likely a 50/50. To get Void Antlered Deer to produce it, you must feed it Hollyhock, and then right click (tap on mobile) it with a Small Glass Bottle. It does not matter if the deer is tamed or not.

• This item can even kill you in creation mode if you get unlucky. They really did mean it when they said “Be careful!”
• Void milk does not have any direct attributes, as it does not restore a fixed amount. It either restores your Hp to full, or kills you.