This info is about spikes on the floor, see Spikes (Wall Hangings) for hanging ones
You see spikes.
Location
Ancient Temple, Formorgar Mines, Greenshore, in the caves of Treasure Hunt Island.
Notes
They come out of Strange Holes and will stay protruded for 3 seconds, followed by 1 second of withdrawal. Note that these will only harm you when you walk on them; this means you can safely stand still on the Strange Holes they appear from.
Spikes in Greenshore
See also: Blades