This is a VERY elaborate costume worn by the actor Nicholas Worth in his portrayal of Lonzak in Star Trek: Voyager. Lonzak is the chief henchman of Dr. Chaotica in the Holodeck program 'The Adventures of Captain Proton' (a throw-back, black and white serial in the style of Buck Rogers) that was run on a few occasions by Lt. Paris and Ensign Kim (with other VOY characters joining in). The costume was first used in the 5th Season Episode, 'Bride of Chaotica':
The Lonzak costume made its second and final appearance in the 7th Season Voyager Episode, 'Shattered'. In this episode the character of Chakotay is travelling through the ship and is transitioning to different time-frames - including while the ship was dry-docked in Mars orbit. He is collecting contacts, and overcoming obstacles, in each time-frame while figuring out how to resolve the problem. With an early version of Janeway (from dry-dock) he enters a time-frame when the Captain Proton program is running. Please note that there is a different helmet on Lonzak.
