millepora alcicornis

from The Collaborative International Dictionary of English v.0.48

Sea ginger \Sea" gin"ger\ (Zool.)
   A hydroid coral of the genus {Millepora}, especially
   {Millepora alcicornis}, of the West Indies and Florida. So
   called because it stings the tongue like ginger. See Illust.
   under {Millepore}.
   [1913 Webster]