The sixth of the Chinese zodiac is 蛇– ‘snake/serpent’.
蛇 is pronounced shé.
The character蛇（shé）was first seen in the oracle bone inscriptions. Its original meaning was an animal with a long, round body, scales and no claws. It also means walking along the ground, representing a mysterious way of living. Later,it extended to the meaning of looking like a snake amongst other meanings.
打草惊蛇 (dǎ cǎo jīng shé)
Literally, hit the grass and startled the snake in the grass. Later, it was used as a metaphor for not being cautious, but it made the other side is on guard.
杯弓蛇影 (bēi gōng shé yǐng)
Literally, mistook the rainbow in the wine glass for a snake. Metaphor for fear caused by suspicion.
人心不足蛇吞象 (rén xīn bù zú shé tūn xiàng)
The metaphor is that people are not greedy, just like a snake wanting to eat an elephant.