虫
チュウ, キ, むし, む
insect, bug, temper
JLPT2 G1 S6 F1351
A depiction of a snake, specifically a pit viper rising to strike. However, 虫 was adopted as a Shinjitai (new character form) to replace 蟲, according to which 虫 bears the meanings *insect*; *bug*; *worm*. Note that 虫 has a much broader sense than the English "insect," and can refer to a wide spectrum of life forms.
[Full Kanji Etymology List]