...he inadvertently used my Craftsman 19.2V fluorescent lantern flashlight as a lifting block...
We were bleeding the rear brakes. Car was up on jack stands, axle dangling. I'm pumping the pedal and topping off the fluid, he's under the car at the wheel cylinders. He had balanced the light on the axle under the reinforced unibody/frame that goes over the axle. When he was done he got out, jacked the car up by the differential, pulled the jackstands, and lowered it down. As we're getting ready to bleed the front brakes, I notice that the rear end is sitting unusually high, then I notice the light. He starts dragging the floor jack to axle again, but I divert him to the front leaf spring mount so to not add even more stress to the flashlight...
Surprisingly the light still works despite having had all of the weight of the rear half of the car sitting on it. The top deformed where the body pressed on it and one of the seams is a little wider than it was before due to deformation, but the battery is intact and the bulb didn't break.
I do not advocate using one of these lanterns as a jackstand, but I suppose that if one absolutely must, it may work in a pinch...