Medusa have +2 Dexterity, +1 Intelligence, darkvision 60 feet, and have a natural weapon with snake-hair that can grant the poison condition if the target fails a Constitution save. They have advantage against poison effects of all kinds and at 5th level they gain a paralyzing petrification gaze which can permanently petrify a target if they fail their Constitution save 3 times. Unlike other features the petrification DC is not modified by ability scores or proficiency bonus, starting at a mere DC 8 and growing to a maximum of DC 14. Still, the poison condition is a very useful status effect to inflict upon enemies, and further attempts at petrification on the same target in battle are bonus actions and the save is made at disadvantage, and 3 failed saves even from different medusae cause instant petrification. A party of medusa have a good chance of 'stun-locking' an opponent, so they're a pretty good choice as a race.