The Emergency Security Gorn, or ESG Mark-1 for short, was a sophisticated holographic program used aboard Starfleet's first Emergency Medical Vessel in the latter part of the 24th century. The ESG Mark-1 was an Emergency Security Hologram based on the Gorn species. The Doctor, one of its developers, espoused that the ESG Mark-1 had proven to be a fierce hand-to-hand combatant during tests. Unlike the Gorn species, the ESG sported a tail, which the Mark-1 also utilized in combat. These holograms spoke flawless Federation Standard. (VOY novel: Unworthy)