With a STAB boost and a Choice Specs boost, Unown can at best 2HKO all non-Life Orb variants of Poliwrath with Hidden Power Psychic. At best, it inspires fear in the mighty Kakuna. Why are you using this again?
Choice Specs is the item because Unown has only one possible move, so the drawback of being locked into a move means nothing. More importantly, the item brings a nice pop of color to Unown’s drab black and white color scheme. Investing in Unown’s Special Attack and Speed will allow it to do the most damage possible before it is taken out, which still won’t be much.
The reason why you are using Unown is unknown.
Use a better Pokemon, and then build a team around it.
— I appreciate the Smogon strategy article on Unown.