!hurt player can be applied as a parent to objects that will hurt the player. !hurt ghost can be applied as a parent to objects that will hurt the ghost of the player. !hurt can be applied as a parent to objects that will hurt both.
Press space to swap between ghost and player.
This is a basic system which spawns in a fake player as a substitute of turning collisions off. The only relatively difficult thing about this project was saving the velocity between players.