The ring look like a spider with large fangs and long legs that wraps around your finger and once you attune to it the fangs sink into your skin and leg wrapped around your finger tightly and your form changes just a little into a dark way 

 After your charisma go down by one but your wisdom go up by two, you can see in non magical and magical darkness, you are immune to the poison conditions  

Notes: You must take roll 1d4 points of piercing damages if you wish to attune to it