I've seen a few belly landings and only planes bigger than a beechcraft baron made sparks.
The beech just slid to a stop at frederick, MD airport................it did have a very small playboy logo on the tail so wondering who owned it.
I saw a sweet mooney 231 belly in, strike the prop, and take back off to land properly and the aluminum prop actually made sparks.
Lucky for the pilot, the prop had broken off about an between .80 inches and 1.3 inches off of each tip and the plane was able to go around and land with only an expensive engine teardown/inspection/rebuild and a bit of skin repair from the tail strike.
I guess aluminum can make sparks....which I though impossible until then.