Rare Weapon (Light Crossbow), Loading, Range 80/320, Two-Handed, Requires attunement

Power of the Elements. This crossbow is imbued with the powers of all four elements. It can however only benefit from one elemental power at a time, and switching between them requires a bonus action. The elements grant these following effects

• Fire: When you hit with a ranged attack using this weapon, it deals an extra 1d8 fire damage.
  
• Water: The target’s weapon becomes engulfed in a small vortex of water, which slows down their attacks. The target is pushed 5 feet away from you, and gains a cumulative -2 penalty to their next attack roll made within the next minute.
  
• Air: Gives a +2 bonus to attack rolls made with this weapon. The range of the weapon is doubled and it loses the Loading weapon property. 

• Earth: If the target has natural armor, or is wearing medium or heavy armor, they gain a cumulative -1 penalty to AC (to the minimum of 10 AC) until the end of your next turn. The area within 5 feet of the target also becomes difficult terrain until the end of your next turn.