Martian Drone

Only during Martian Madness, which itself only starts once a probe escapes with a scan of you, so this is strictly a post Golem problem. It ignores terrain completely on the way in, so a roof over your arena buys you nothing here even though it stops most of the event.

The routine never varies. It climbs until it is sitting just above your head, then drops, and once it is close enough it detonates rather than trying to touch you. The blast covers area, so stepping aside at the last moment is not a dodge. The answer is to shoot upward and kill it while it is still lining up, because reacting to the dive itself is already too late.

Standing in a tunnel breaks the routine entirely. It stops committing and simply hovers over you for as long as you stay in there, which parks it while you deal with the rest of the wave. Corites can be shut down the same way.

A drone that blows itself up contributes nothing toward invasion progress. A wave carrying a lot of them drags the event out longer than it should, so killing them yourself is worth doing rather than eating the blast and moving on.