Using a stony wand on a monster while you used stairs means you're stuck forever in the stairs. impossible to move forward because there's now a wall where there was a monster, and for some reason you can't go back in stairs until you've actually left the stairs tile.
i can't count how many times i killed my own summonables, not knowing i could displace them using the arrow keys. i thought that if they cornered you, you pretty much had to kill them