I will admit that the last idea was indeed smart, and I dont think the other ones (or at least most of them) were that good of ideas for a type of discussion like this. Only choose attacks that really give Olimar problems, like the blizzard wall. Things like falco's lasers... dont' give us problems, tbh.
So think of a top/high tier and one specific attack that they have that drastically changes the matchup.
First thing that comes to mind is Snake's Ftilt, but that was (to an extent) discussed in the Matchup Thread. But something like that. But if you wanted to use that, that's fine too.