This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Spriggan (Cornish)
Spriggans have often been depicted as grotesquely ugly, wizened old men with large childlike heads. They were said to be found at old ruins, cairns, and barrows guarding buried treasure. Although small in stature, they have often been considered to be the ghosts of giants and retained gigantic strength, and in one story collected by Robert Hunt, they showed the ability to swell to enormous size.
Hunt associated these spirits with the hillfort known as Trencrom Hill in Cornwall. Spriggans were notorious for their unpleasant dispositions, and delighted in working mischief against those who offended them. They raised sudden whirlwinds to terrify travellers, sent storms to blight crops, and sometimes stole away mortal children, leaving their ugly changelings in their place.