Updated: Oct 19, 2021
When the snake and the mongoose fight together, most likely, the mongoose will win!
Snake is a dangerous and poisonous animal which can move fast without legs, by using their scales. Mongoose is a small non-dangerous compared to humans. But, the mongoose wins in the fightings due to its exciting and active struggle.
Commonly, the mongoose has more mobility. When it starts fighting, the hairs stand tall. So, the snake can't bite it powerfully and, the dangerous snake venom can't enter inside the mongoose. The muscle of the mongoose nicotinic acetylcholine receptor carries many mutations in the ligand-binding domain. So, it won't die fast.
However, mongoose cannot defeat the largest, and the most powerful snakes like big cobras and Anacondas. They have more particular attributes and abilities than other snakes.