Snake

The plural of Snake is Snakes.

The symbol of the Snake is often used to indicate Secret Wisdom. (See "Who's Afraid of Freemasons" by Piatigorsky page 136) Wisdom can mean useful Knowledge.

Doctors use the symbol of two Snakes wrapped around a pole.

Snake is a common term used for Serpent.

The Snake is often blamed for causing Eve to eat the forbidden fruit that is said to have grown in the Garden of Eden.

Most Snakes are harmless and helpful to mankind while a few are poisonous to mankind.

Some consider the Snake to be a symbol of the Devil, or of Satan while others consider it to be the symbol of Wisdom, or of Knowledge.

Could it be that the Serpent or Snake was considered to be the Devil because the snake represented Knowledge or Wisdom and the early Christians did not much like people who had enough wisdom to be be Freethinkers.