spicule

noun

• 1 technical a minute sharp-pointed object or structure that is typically present in large numbers, such as a fine particle of ice.
• Zoology each of the small needle-like or sharp-pointed structures of calcite or silica which make up the skeleton of a sponge.

• 2 Astronomy a short-lived, relatively small radial jet of gas in the chromosphere or lower corona of the sun.