Frank J. Wilstach, comp. A Dictionary of Similes. 1916.
Slippery
Slippery and smooth as a serpent.
—Arne Garbog
Slippery as an eel’s tail.
—John Heywood
As slippery as the Gordian knot was hard.
—William Shakespeare
Slippery as ice.
—Theodore Watts-Dunton