Losing levitation over water/piranhas/magma deals damage twice
If you lose levitation (either by staff of levitation running out, or unequipping an item) while hovering over water, piranha water, or magma you are subject drowning, water/fire damage, and piranhas twice. The first damage message is actually shown before the "You float to the ground" message. If you get killed by the second instance of damage, the game allows you to save a dead character.