Theres two types.
Chalk: Draw on things! (walls, floors, ect) Purchasable at spawn $99
Revival chalk: Obtained in the mansion store for $1499 This chalk allows you to revive a teammate. But you have to use a gold orb.
Instructions; Draw a circle around the dead player
Throw a gold orb at said player
Get revived
useful for team dives and uses two items.
Of course you would need to make it so that theres a respawn button instead of auto respawn.