Bay Thoroughbred with gulastra plume. Gulastra plume, also called silvertail, is an apparently random silver/partial silver tail, most commonly seen on bay horses. It is thought to be connected to the sabino complex but the genetics are not yet known.
Interesting genetic fact shared from Judge My Ride, "When two copies of the cream gene appear on a bay base coat, Perlino is the result. Cremello is caused by the presence of two cream genes on a chestnut base coat.