Spriggans were fundamentally a good species and evil types of them were very rare. That said, both good and bad ones were unmanageable when they went on a rampage.
Spriggans could freely change their size from small to large.
In English lore, Spriggans were said to be the bodyguards of faeries. Although small, they were usually considered to be the ghosts of giants, that is the reason why they could freely change their size from small to large.
Spriggans were depicted as grotesquely ugly, wizened old men with large child-like heads in English lore.