It may be something sweet, that dried up on that part of the wall......find where they are getting in the house, wet a small piece of napking, t.p. wet it, cram it in the hole, better than spraying POISON in your house, wash the area down they "gather" on.

I use vinegar and dish liquid mixture. Throwing baking soda on the first if applicable.

I've had a bit of an ant problem in my room recently, and I noticed today that they were grouping up on random parts of my wall. There were two spots on the corners of the ceiling next to my window, and then two other spots just in the middle of nothing on the same wall.

I would get it if there was something spilled there or something, but due to where they were, there's no way. What would be the reason for this?