An ensign of the USS Titan-A whose identity is taken by a Changeling saboteur in 2401, exposed by Jack Crusher and later destroyed by Seven of Nine.
Ensign Foster is a junior officer aboard the Titan in the third season of Picard, played by Chad Lindberg. The man seen on screen is a Changeling infiltrator who has taken the real officer's place.
In Seventeen Seconds, while the Titan hides in a nebula from the Shrike, the impostor sabotages the ship so that it leaves a trail. Jack Crusher catches him at work and is attacked, and during the struggle the saboteur's face briefly loses its shape, proving that Changelings are involved in the conspiracy.
In No Win Scenario Seven of Nine is set to hunt the intruder down. It tries to approach her in the form of Sidney La Forge but uses the wrong name for her, and Seven shoots it. The remains give Beverly Crusher her first evidence of how the new Changelings differ from the old.