From Worms Knowledge Base
This weapon, fired like a gun or perhaps Flame Thrower, propels a sticky blob of glue at a worm or the terrain. Any worm that comes into contact with the glue becomes stuck, or 'anchored' and is unable to move without help of the teleport. The worm is still able to use weapons however.
The blob remains on the terrain permanently, able to stick to more worms when the previous worm has escaped, but burns up in contact with fire, and eventually degrades away regardless.
'Anchoring' worms is already possible with a game option of the same name. Except you would have to restrict it further, preventing use of rope and jetpack.
The 'blob' of glue, when unattached to a worm, would have to act as a mine-like object, getting thrown about by explosions. With no bounce setting, of course. When it is stuck to a worm, it will get carried to wherever the worm is blasted. Upon landing, the worm remains stuck.
Trapping worms can already be done with such tools as the girder, but this is a crude method and the Glue Gun achieves the same thing without preventing the use of weapons, and so may not be considered as 'cheap' as the girder block.
The Glue Gun gives the user obvious advantages. In games where crates are ubiquitous or water is rising fast, trapping opponents or blocking off important tunnels with blobs of glue can only be beneficial, if a bit annoying for the enemy player.
You might think a weapon that hinders the opponents abilities would be frowned upon by the masses, but it isn't really that restricting. It is only movement that is restricted, and worms environments are usually restricting enough as it is. If it provides an alternative to the ever-dishonourable girder-prison, who can say no?
P.S. Like mines, glue could be deposited on the terrain before the action begins, as well as being available in the form of a strike.