Sniper Shell

Sniper Shells will aim at the player with a red laser, then fire a single high-speed bullet. They tend to stay far away from the player and are often posted on distant vantage points surrounded by pits.

Professional
Professionals behave identically to Sniper Shells, but their bullets burst into more bullets in all directions upon hitting an obstacle.

The Professional's laser sight is colored green, instead of the standard Sniper Shell's red. This trait can be used to identify the greater threat from far away.

Trivia

 * Professional's namesake and appearance (a black skullcap and small round sunglasses) are a reference to the movie Léon: The Professional.
 * The line "EVERYONE!" is likely a reference to this iconic scene from the movie.
 * While the Professional's sprite in the ammonomicon has a copper colored bullet tip, the actual sprite and the ammonomicon art have a standard gray bullet tip.