The Grave is a dream sequence encountered after reaching Dose Tier 2 or 3.
After a brief, stoic walk through the woods, a dead body can be found. The dead body will ask the player if he wants to lay down in the dug grave with him. There is a Shovel that can be picked up next to the grave.
If the player doesn't act, after a while, a menacing scream will be heard and the corpse will disappear if the player looks away. A Black Chomper will attack the player from the woods, leading to a very difficult fight.
There are several ways the dream can end, some with their own consequences: