Tyrant 091 was an experimental Tyrant, derived from the T-103 model.
This Tyrant was the first attempt at engineering a Tyrant with the t+G virus. It was considered a failed experiment due to the lack of an electrical current, which the t+G virus was designed to produce. It also suffered from an exposed major organ: the heart, which stuck out of its back, making it more vulnerable to attacks. Unlike most Tyrants, instead of arms with claws the T-091 had grown tentacles, which acted as its fingers.