An idea that just popped into my head. Also because I thought it was pretty interesting.
The gun basically looks like two planks with a bottle of elmer's glue sandwiched in between the two of them. If shot at a surface, it will leave behind a model of a glue puddle that will last for only 30 seconds. If a player steps in the puddle, they will be immobilized for about 5 seconds, similar to if they get hit by the "Magic - Ice" weapon. If the player becomes unstuck, the glue puddle will disappear instantly. If shot directly at a player, it will still immobilize them, but the player is now encased in a cocoon of glue, and will be immobilized for only 10 seconds. If the glue was shot at a wall and the player touches it, nothing will happen.
It will also deal very light damage if shot directly at a player.
So could anybody make this into an add-on? or not?