Trigger collider to trigger with something that is not a rigidbody.

I have a box collider that is trigger and a bullet object with no rigidbody that just shoots forward.

I need it to be registered by trigger, but it says that only bodies that have rigids register, but I don't want my bullet to be affected by physics.

If you don't mind your bullet to move very fast (instantly) try using Raycast. Cast a ray from the gun to the target. The target must have a collider but the 'bullet' is nothing but a ray.

The `isKinematic` property of rigidBodies does exactly this -- turns off actual "physics" while still counting as having a rigidBody for things like collisions. It even disables the ability to set velocity.

For fast motion, change collision type from `discrete`. Of course, for super fast, use the RayCast trick, above.