What Native American leader famously resisted U.S. control and was killed in 1890 leading up to Wounded Knee?

Sitting Bull

What creature had snakes for hair and turned observers to stone? Who performed the song "Shape of You"? Which amphibian famously secretes a toxin powerful enough to kill up to 10 people? Who provided the voice for the conductor in the animated film 'The Polar Express'? In human anatomy, what fluid is stored in the gallbladder?