Some creatures are incorporeal by nature, while others (such as those that become ghosts) can acquire the incorporeal subtype. An incorporeal creature has no physical body. It can be harmed only by other incorporeal creatures, magic weapons or creatures that strike as magic weapons, and spells, spell-like abilities, or supernatural abilities. It is immune to all nonmagical attack forms. Even when hit by spells, including touch spells, or magic weapons, it has a 50% chance to ignore any damage from a corporeal source (except for positive energy, negative energy, force effects such as magic missile, or attacks made with ghost touch weapons). Nondamaging spell effects affect incorporeal creatures normally unless they require corporeal targets to function (such as implosion) or they create a c