The BTD3 Spike-o-pult hurls a spiked ball at bloons, but unfortunately with slow fire rate, popping 12 bloons each. It is used in BTD3 to wipe out clustered, large-numbered groups of low ranked bloons. It first appears in BTD3 but was converted into an upgrade for the Dart Monkey in BTD4, BTD5, and BTD6.
- 1-1 Faster Reload: Increases fire rate.
- 1-2 Juggernaut: Much larger piercing.
- 2-1 Wider Radius: Longer range.
- 2-2 Multi-shot: Shoots 3 balls per shot.
- The Multi-shot was taken as the Tier Four upgrade in BTD4 and replaced with the name Triple Shot.
- Juggernaut is the 4th tier of the left path of the Dart Monkey, with its addition of doing extra damage to Ceramic Bloons, popping any bloon type, and having a much bigger ball.