"ssSSLY!"
Fort save: 1d20 + 3 ⇒ (13) + 3 = 16
bite v red (smite evil!): 1d20 + 5 ⇒ (10) + 5 = 15 damage (+1 if red is evil): 1d2 - 1 ⇒ (1) - 1 = 0 Save v poison DC 11
Viper Poison Bite—injury; save Fort DC 11; frequency 1/round for 6 rounds; effect 1d2 Con; cure 1 save. The save DC is Constitution-based.
Note Slywinder is Tiny-sized.