A variation on the classic upper decker, combined gracefully with the dry dock.
Step 1: Turn off the water for the toilet at the valve.
Step 2: Perform one last flush, draining the remaining tank water.
Step 3: Perform an upper decker, but do not turn the water on. A loose stool is recommended here, with inspiration being drawn from the name.
Step 4: Leave the toilet, water off and bowl emptied, with the chili base in the tank.
Ideally, the smell will draw attention. The unfortunate victim them turns the water back on, thus "making the chili." Next, a flush...and aged (or "simmered") brown streams of Texas brown flow into the bowl. A true masterpiece, intended only for the very brave!
"I'm playing a long game. My in-law's bathroom has a chili waterfall simmering--can't wait until they find it!"