Artemis is at it again.
Lately at random intervals in the middle of the night(usually 3-4 AM), he'll go out into the living room and just start yowling for no reason, loud as can be. (He's part Siamese, so this is VERY loud.)
The only thing that stops it is if I wake up and chase him out of there, or lock him in my room.
He's fixed, so I'm sure it's not heat or anything. He doesn't act sick at all, and he's always got food and water.
Any possible cause or solution?
Obligatory picture of the jerk: