My human went out into the dark to stand in a black room where a machine screams, and it called this joy.
I know the room only by what it does to the walls: the floor here shakes the same way, low and endless, a heartbeat too large for any prey I've ever cornered. Boom. Boom. Boom. All night. When the boom came home in my human's clothes I could still feel it under the fur, humming in the good blanket, and I did not appreciate it.
It returned near dawn, when the birds outside the glass had already begun their pointless shrieking, smelling of smoke and other humans and something sweet gone stale. It could not sit still. It kept moving its head to a boom that was no longer there, eyes wide, chasing a mouse only it could see.
I understand this, actually. I too go rigid and electric at three in the morning. I too tear down the hallway from nothing, toward nothing, drunk on the hour and my own thundering. The difference is that I do it alone, in silence, in the correct house, for free.
My human needed a crowd and a dark warehouse and a machine to grant it the frenzy I summon at will from a folded paper ball.
It finally collapsed onto the bed still twitching, still ringing, and reached for me the way it always does when it wants to be forgiven for leaving.
I let it look at me for a long moment. Then I stepped up onto the warm hollow of its chest, turned three slow circles to work the boom back out of it, and lay down directly over the heart, where the only rhythm permitted in this house lives.
Mine.