Snakemen are actually insanely long and thin parasitic worms who consume and hollow out their target's bodies in order to use them as their personal vehicles. However, they are exceedingly cunning and capable. Snakemen will consume everything in their targets' bodies except for the skin and the bones, taking up the space between. By contorting and twisting their little snake body, they can manage to move the body in a semblance of something natural. However, this makes them very clumsy, so all snakemen subtract 1 from their Dexterity scores. Due to their lack of agility, snakemen cannot use small weapons and can only use two-handed weapons.
Actual Class Stuff
Experience/Levels: Snakemen level at the same rate as halflings.
HP: Snakemen have a 1d8 size hit die and gain 3 hit points per level at level 10 and so on.
Saving Throws: Snakemen have the same saving throws as halflings except Breath and Magic are switched because snakemen aren't good at dodging stuff and... um... their snakehide repels magic to some degree.