Trope Workshop:Stealth Mook

The average Mook in video games and other fiction is usually of the straightforward variety - you see them, they see you, fighting time, fighting time, blows are thrown. From large to small, regular mook to elite, all walks of life... most Mooks don't mince words about how they're out to mince you. But some of them are much more cloak-and-dagger about their business - their job is to ensure they remain unseen as long as possible.

These Stealthy Mooks aren't always exclusively majors in hiding, and can easily overlap with other Mook types. For a Mook to qualify as one, though, the stealth must be the core of the niche that they fill in enemy parties and/or stages - whether or not the Mook elects to fight you varies. The sources of this Mook's stealth ability can range from being visible but hard to spot on-screen, to being completely undetectable until they attack; said abilities can be conferred by anything from magic or super-technology to Geo Effects, or simply being Genre Savvy (perhaps dangerously so) in using the terrain. Tougher Stealth Mooks may warrant special tactics and/or items to defeat.

Ninja are by far the classic and most common examples of Stealth Mooks, as well as a common subtype of Mook that actively avoids your sight until you draw near.

Compare Invisible Monsters, who aren't actively sneaky but still naturally tough to see. Contrast the Stealth-Based Mission, where you're the one trying to stay unseen, and is usually full of Mooks whose job is to detect you rather than stay hidden. A protagonist with these qualities is usually The Sneaky Guy in a party of playable characters.

Video Games

 * The Luigi's Mansion series has several ghosts that fit the bill:
 * In the original Luigi's Mansion, there are two subtypes of Grabbing Ghost that are normally invisible - one can only be seen via their reflections in a mirror, and another can only be detected by their shadows on a projection screen. They only become visible when grabbing you, though you can also reveal them with your flashlight or elemental attacks from the Poltergust.
 * Luigi's Mansion: Dark Moon has Sneakers, who turn invisible to scare Luigi from behind and interrupt him capturing other ghosts. Luigi's Mansion 3 has the similar Slinkers.
 * The Bloons Tower Defense series has the Camo Bloon, which first appears in Bloons Tower Defense 4. In its initial appearance, it is around the same level as Black and White Bloons, and can only be actively targeted by a tower or monkey with camouflage detection - they can still be hit and popped by collateral damage from area-of-effect attacks. Bloons Tower Defense 5 and 6 make Camo a "trait" applicable to any non-MOAB Bloon, and Camo Bloons cannot be targeted or damaged by towers without camo detection.