A stationary turret that can shoot explosive bolts at mobs or players in its AOE. The way it would work would be a reskinned armor stand, with a reskinned saddle, that you can sit on to control the cannon, and a furnace to hold the ammunition and govern the reload time. Whenever a player would sit on the cannon, it would give them a special stick to direct the cannon and fire the cannon. When the player exits the cannon, the stick disappears. The cannon would require a gunpowder dust pile, and fire charge/firework star as ammunition. Any entity in a 6 block radius would be poisoned blinded, and slowed for around 10-15 seconds, and the cannon has a reload time of 20 secs. The cannon would look something out of the Ming Dynasty. The explosion damage would be equivalent to 2/3rd the damage of a TNT block. (the cannon seems balanced because of the expensive cost of firing)