I'm showing you the picture of a character and you tell me if you would like to play that character in your game.
http://uberhumor.com/wp-content/uploads/2016/08/mQGQAbW.jpg
I think it would be hilarious to play.
Would the opponent be considered flat-footed is the weapon is invisible but you're not?
Unseen
Price +2 bonus; Slot none; CL 7th; Weight —; Aura moderate illusion
DESCRIPTION
Restriction This special ability can be placed only on a melee weapon.
Upon command, an unseen weapon can be made invisible, including any scabbard, sheath, or similar accessory used to hold the weapon. A careful search will still reveal its presence, but purely visual examination will not. While invisible, an unseen weapon causes its wielder to take a –1 penalty on attack rolls unless she has the Blind-Fight feat or is able to see invisible objects. On the first attack made with an unseen weapon during a combat, the defender is denied its Dexterity bonus to Armor Class unless it has the Blind-Fight feat, is able to see invisible objects, or is specifically aware that the wielder is using an unseen weapon. An unseen weapon is considered to have total concealment for attacks or effects directed at it, such as combat maneuver checks made to disarm, steal, or sunder it and disintegrate or rusting grasp.
CONSTRUCTION REQUIREMENTS
Cost +2 bonus; Feats Craft Magic Arms and Armor; Spells greater invisibility
Would I play it? No.
Would I find it absolutely hilarious for someone else to play it, and encourage this at the table? Absolutely.
Ha! Doppleman has you covered, courtesy of Ultimate Intrigue.