Not to the confused with the SV-001 Type-R, a gold colored Metal Slug.
The Golden Slug is a Slug exclusive to the Pachinko version of Metal Slug 3.
The Golden Slug is a flight-based Slug similar to the Slug Flyer and Slug Copter. Unlike those two, the Golden Slug acts more akin to a bird (which it's obviously shaped after): flapping its wings to maintain flight and making loud squawks.
The Golden Slug has no Vulcan attached to its body. Instead, it shoots a barrage of missiles located between its "feathers". A laser beam is located inside its mouth.
The Golden Slug appears in scenes where the Regular Army is battling against the Martians. Marco is able to ride it in the Rootmars fight. Before he can do that, the player must stop a roulette that contains an SV-001, a Slug Gunner, and the Golden Slug itself.