How to make player have weapon when player clicks item in inventory.

[quaint agate]

I want when player press item in inventory it makes the player have a specific weapon (still keeping item in inventory)

[fallow tiger]

What? Explain more about this

[quaint agate]

Ok so basically what i want is...when you press an item in your inventory (in this case its the tornado in the players inventory) you get a weapon when its pressed, not the tornado image

So basically im trying to make...a skill