The creature has plus 2 to AC and immoto poison damage 

At level 1 you gain one form to turn into at anytime (Bonus Action) while transformed you have an AC of 20, movement speed of 75, can't attack but if they hit another creature mist pass a Dex/Strength Saving throw(it chooses) 8 plus strength plus your profiencey bonus or it takes 2d8 buldening damage and is prone. Gain additional forms at levels 6(2), 10(3), 15(4), and 20(5)(total forms).

This gives Advantage on strength checks and a plus 2 to consistutuion and Dexterity.