Spike (Super Mario World)
From the Super Mario Wiki
Spikes are thin, short, smooth-sided, pencil-shaped wooden pillars. They come down from the ceiling or up from the floor. Most don't retract all the way, leaving their point exposed. They are found in Super Mario World in the Chocolate Fortress and #7 Larry's Castle. They are indestructible obstacles, but can be touched from the side unlike a Skewer, which, unlike the wooden stakes, have spike-studded sides.