Heisenberg's cat

My cat, Otto, likes to play in the tub behind the closed shower curtain. I can hear him in there, making a lot of noise, thwap-a-wap-a-wap-a-thwap, pause, thwap-a-thwap-a-wap-a-thwap, pause, pause, thwap...

If I open the curtain to see exactly what the hell he's doing, all I see is him crouched down, staring at me with dilated pupils.