An aranea can use its action to polymorph into a Medium beast or humanoid creature of CR 2 or lower, or from another form back into its own form. The aranea retains its Int, Wis, and Cha scores and its current hit points while polymorphed; otherwise, it takes on all the attributes of the adopted form. It can cast spells if the adopted form can provide the spell's verbal and somatic components, and it retains its paralytic poison trait if the adopted form has a bite attack. A shapechanged aranea reverts to its natural form when slain.