Rolling Fire CR 4
Source: Paizo Blog
Also known as a faeu boulanger, rolling fire is a trapped soul that was lost in a tragic fire fatality. The haunt manifests as a spectral sphere of ectoplasmic fire that seeks to scorch and burn the living in a grisly reenactment of the conflagration that created it.
The haunt appears as a large ball of spiritual flame emitting agonizing screams. The haunt attacks the first creature that enters its area as a flaming sphere spell (save DC 13).
Turning one’s coat inside out confuses the faeu boulanger and prevents attack. A knife must then be stuck blade-up in the ground of the haunt’s area; when the roaming spectre rolls over the blade, it impales itself and is destroyed.