Vaankara

The Vaankara was a Vulcan vessel that entered the Delphic Expanse in December 2152 searching for the Seleya. Less than two days later the Vulcan High Command received a distress call. Six hours after that they received a transmission of the crew killing each other bare-handed. An hour later the starship was destroyed; there was no evidence of a malfunction or an attack. (ENT: "The Expanse")

It was later discovered the crew had been driven insane by exposure to trellium-D due to a complete loss of emotional control. (ENT: "Impulse")