@bearsupply

It's a map marker, aka a "Light Beam". It's from a map add-on called the "Glass Bead" which lets other Survivors (with a map and this add-on) leave markers like these on the ground for all other Survivors to see.

Think of it as a signal to give you a vague idea of what another Survivor wants you to see/know. Most Survivors that use it just meme around with it, I hardly see anyone actually use it for it's intended purpose.