Sorry, Saturdays are the only days I get to play Minecraft so yeah.
My sister raided a Pillager Outpost and got a horn. She blew the horn and went back to a nearby village. A while later my sister got attacked by a ghost pillager. She couldn't see or hit it, but it was shooting arrows at her. She hid in a house for a couple of minutes and it went away.
I said that it was an enchanted horn like the one from Narnia, but instead of summoning Peter Susan Edmund and Lucy, it summons some sort of phantom pillager.