we keep 2 cheap cat cubes we got at walgreens in the hallway upstairs. the kitties like to go in there or the tunnel with their toys after we go to bed and play for a while. Last night, my hubby called from the living room for me to go look where the cat cubes were..they were at the bottom of the stairs! He said he saw Squeek running away from there. When I went to look from upstairs, i saw Lickorish about halfway down the stairs, looking down. Not sure if she was involved too or if she went to see what the commotion was. At least everyone was ok. They've tumped the cubes on their sides before, but never moved it far enough to actually slide down the stiars. We've left them at the bottom of the stairs for now.