Benthan

From Memory Alpha, the free Star Trek reference

The Benthans are a warp-capable species from Benthos in the Delta Quadrant.

Physically, they are humanoid with a large nasal structure that extends up to their foreheads.

They were encountered in 2374 when the USS Voyager met a Benthan test pilot, who called himself Steth. He was flying an experimental ship equipped with a coaxial warp drive.

In fact, a shapeshifting alien had switched places with the real owner of this body some time earlier. The alien switched again with Tom Paris and later with Kathryn Janeway before being apprehended. (VOY: "Vis à Vis")