As you progress to the later levels, players will encounter a cannon that shoots out nets. While players cannot remove the cannons, they do have to remove the nets that it shoots out as part of their level mission.
Players will need to make matches adjacent to the cannon to charge up the canon. Once it's charged up, it will shoot out nets onto the puzzle board. Depending on the level mission, the cannon may shoot out more or less nets.
To remove the nets, players will either need to make matches where the nets are or use booster items to remove.