3* weapon
damage type: normal
normal: shoots a glob of glue 2 tiles away (can be changed). If it hits an enemy, it does damage and slightly slows them for 1 sec after hit (can be changed).
If it falls on the ground, causes no damage but enemies will be suffer medium slow while walking on and 1 sec after walking off 'glue' tile.
reload after 4 shots, glue tiles disappear after x amount of time,
Charge: Fires a spray 6 tiles wide and 3 tiles long that damages enemies within up to three times and slows them like the normal shot. Also transforms any 'glue tile' into a solid structure that disappears after taking a hit from knights and 2 hits from enemies.
The upgrades of the gun could function in the same way, except inflict statuses, have higher damage, and the 'solid glue' takes more hits from enemies before being destroyed.
http://wiki.spiralknights.com/Stun