- Geth Ghosts are by far the most dangerous variety of hopper, because their Assassination ability does heavy damage and can easily one-shot Shepard on higher difficulty levels. Worse, the red beam for the lesser Geth Sapper's sabotage ability looks exactly like the Assassination warning beam, so you can easily be lulled into a fatal trap if you're not paying attention.
- Geth Ghosts, like all Geth Hoppers, are lightweight and lightly armored, making them vulnerable to gunfire. The problem is getting them to hold still long enough for a clear shot. Happily, they are usually encountered indoors, and a Hopper usually leaps back and forth between two positions across a room, allowing you to hit them on their return jump.
- Physics-based biotic attacks, especially Throw, will inflict heavy damage against Stalkers. Lift works nicely to hold them in midair, especially if you're using a sniper rifle.