Collisions without rigidbody.MovePosition

Hi.

So, I know how to do collision checks when using characterController.Move or rigidbody.MovePosition, however in my project I have a ghost that the character can move around with the mouse. I don't want this object to be affected by physics, or prevent it from going through objects, I simply want to know when it's colliding with something to give it a different color.

It's impractical to add a RigidBody to it, so is there any way to do this through using triggers? Or do they also require that something is rigidBody.MovePosition'd through them to actually trigger?