Perma-Spike

"Spikes become almost permanent."

- Upgrade description in BTD6.



Perma-Spike is the final upgrade of Path 3 for the Spike Factory in BTD6. The spikes produced by the Spike Factory now pop 50 bloons per pile and deal 10 layers of damage per spike, making it extremely powerful. Despite the name, but in accordance with the upgrade's description, the spikes are not actually permanent. Due to the Long Life Spikes upgrade at x-x-3, the spikes last between rounds and have a longevity of 4 rounds each. The spikes It costs $18,700 on Easy, $22,000 on Medium, $23,760 on Hard, and $TBA on Impoppable.

Tips

 * Always purchase this upgrade on single-entry-single-exit maps near the end of the track. Then spikes won't be used up immediately, allowing spike stockpiling to slowly make the tower more and more valuable.
 * Likewise, selling a Perma-Spike would be inefficient and a player should only sell it if the positioning was incorrect.  However the Directed Spikes  upgrade can generally solve any problems.
 * It is recommended to purchase the Path 2 Upgrades (Faster Production and Even Faster Production) over the Path 1 Upgrades (Bigger Stacks and White Hot Spikes) as Bigger Stacks only increases its pop count per spike from 500 to 600 and although White Hot Spikes allows it to pop any D.D.Ts that may rush through your defense, a Monkey Intelligence Bureau can easily solve that problem while also providing it and other nearby towers with the bonus as well.
 * Adding Even Faster Production makes production speed approximately 2x faster, so there is little point in purchasing Bigger Spikes unless it's for DDT-popping power.