One final venomous addition

[noodlestsc]

hot just refers to it being a venomous snake. Not entirely sure of the origin, though I'd imagine it comes from the description of a bite since it "feels like a hot knife being stabbed into your body"

Hot usually is a term to describe an object that has a dangerous element inside it (just like saying that snake is hot because it's venomous.) A few examples from the construction world: If an item tested positive for asbestos we call that item hot. We also use that term for electrical items if the juice is turned on (it's either live or hot)