Floating weapon glitch
From Worms Knowledge Base
This is a glitch that works with several weapons, namely those which are supposed to explode on impact with its surroundings - bazooka only being the most prominent one. The Bazooka glitch makes it possible to place these weapons on a worm's head where they remain until eventually their timer runs out and they explode. The weapons it works with are Bazooka, Mortar and Petrol Bomb, and theoretically also Homing Missile, Homing Pigeon and Patsy's Magic Bullet, though these require a special tactic to work (Firing homing weapons without aiming) - also will they start flying toward the center of the map after about one second.
How to do it
Approach a worm which is standing on horizontal ground and below a ceiling (within reach of a Ninja Rope), and slowly walk up one of its sides. You will notice your worm abruptly moving upward a few pixels - the usual behaviour when it's climbing a worm. Keep moving carefully until exactly two of these upward movements have occurred, then select the Ninja Rope and shoot it straight up at the ceiling. Once it attaches, do not move your worm anymore. Instead, select the weapon you want to place on the opponent's worm and release it.
At first, this glitch appears to be useless for tactical purposes. Quite conversely though, it is possible to do around four times as much damage with the mortar as you would shooting it at a worm and hoping for the clusters to hit it. This works only if you do the above climbing up the face of a worm, not its back. This tactic could be very useful in Shopper games, but as it is rather unusual, you'll have to make sure the other players don't dislike the idea of (ab)using glitches.