Falling spike

Falling Spikes are spiked obstacles that fall from ceilings, and appear only in Super Mario World. They are found only in Castles and Fortresses, and are typically grouped together amongst standard Spikes. Falling Spikes will remain on the ceiling until Mario or Luigi approach one, which will trigger it into falling, similar to a Thwomp. Once it falls, a Falling Spike will continue to fall through the floor until it disappears.