Once a month (or so) a colony of very small red ants and a colony of equally small black ants rise to the surface and go to war in an epic battle of miniscule proportions!
They carpet my front walk to the extent that we enter and exit through the garage for about 24 hours.
Then they disappear, I hose away the dead ones, and I don’t see them again for another month.
This is a picture of roiling ants fighting a smallish skirmish just off the front walk:
In previous summers, I tried killing them by placing ant traps, poison (or jumping up and down over and over) but it doesn’t seem to deter them, and they do a great job of killing each other anyway. So now, I just sit on the front steps and enjoy the spectacle.