Tiny snail - is it a baby olive snail?

[hllb]

This guy recently showed up in my tank (Comes out after lights off). It was suggested it’s an olive snail. Could be, though it’s the size of a grain of rice right now so it would have to grow a lot to hit the minimum size of one. Is it an olive snail? Is it something else? I assume he came in on a coral, even though I dip all my corals.

 

[KJ]

Marginella snail remove them.

 

[hllb]

Marginella seems more likely than olive to me. Why remove? Can something that tiny really kill something much larger? Even my dwarf ceriths are huge in comparison. I see mixed recommendations - about 50/50 on good v bad