Spikarian are made out of stone that has been resonated together. The substance that the Spikarian are comprised of is highly mutable; a Spikarian can re-resonate and modify themselves.
The parts of a Spikarian are typically skewed and jagged shards of this special material. They interlock with each other to create a coherent entity. Spikarian do not need to form typical sensory organs; any part of their resonated form can sense. Spikarian, however, generally do form eyes and mouths for aesthetic reasons.