Mortar Monkey is a MilitaryMonkeycard in Bloons Card Storm. Instead of its attacks being controlled by the player, it automatically attacks a random Bloon on the opponent's side (or Dreadbloon if possible) at the end of the player's turn. If given additional ammo, it will use ammo as many times as it can at the end of a turn.
The Mortar Monkey is a somewhat cost efficient attacker, dealing 40 damage per turn. However, its shots are completely random and can only attack at the end of a turn.
Dart Monkey Twins with both charges has a higher damage-per-Gold ratio, at 50 DPT, and the common Alchemist Monkey does more DPT for the same cost, with only delayed damage as an issue.
If dealing with an opposing Mortar, Swarm Red Bloons can make the mortar waste its shots more often.