David Gentry

From Memory Alpha, the free Star Trek reference

For the member of Species 8472 who impersonated this individual, see David Gentry (Species 8472).

David Gentry, serial number 99B3278, was a Starfleet security ensign during the 2370s who was born on Earth.

In 2375, Gentry's identity was unknowingly assumed by a member of Species 8472 as this species prepared to infiltrate Starfleet, and possibly invade Earth. (VOY: "In the Flesh")