Popped Bloons that were glued, [sic] leave a blob of glue on the track.
~ BTD6

Relentless Glue is the fourth upgrade of Path 3 for the Glue Gunner in BTD6. It allows bloons to leave a blob of glue on the track upon being popped. Blobs left on the track will last for 5.0 seconds before disappearing. Although it is an upgrade from the MOAB Glue upgrade, the track blobs do not affect MOAB-class bloons.

It costs $2,550 on Easy, $3,000 on Medium, $3,240 on Hard, $3,600 on Impoppable.


Relentless Glue is another method for the Glue Gunner to counteract its initial lack of proficiency against large groups of bloons, in that it can coat one bloon and transmit to a second target once it is popped. This is crucial, as it allows the Glue Gunner to benefit from the prior upgrade MOAB Glue, coating a MOAB's worth of bloons and creating a large-scale spread of glue to many targets at a time with the assistance of other towers.

In tandem with its slowing prowess to normal and MOAB-Class Bloons, Relentless Glue allows for the solidification of a good chokepoint where bloons are rapidly destroyed from tower fire, creating more glue blobs on the track to slow those that sneak through. In essence, an effectively used Relentless glue combines the powers of all three paths, being longer and slowing more, soaking through layers, and hitting multiple bloons.

Relentless glue virtually requires Glue Soak to function, as the bloon must be glued as it is popped to leave a glob behind, and because of the slower and more widespread gluing, Corrosive Glue can actually deal some decent damage. A 0-2-4 glue is virtually a waste of this upgrade, as relentless glue will almost never take effect, and can only function in extremely niche circumstances, such as combining with Druids or Snipers to instantly pop glued bloons.

Like all Glues, it works best at the start of the track, however, it is actually beneficial to leave its targeting to First, as it can then glue most bloons behind the bloon leader. This is particularly effective in rounds that open with weaker, faster bloons such as pinks or purples. Always combo with Primary Training when possible, as the tower is a lot more effective with even a single extra pierce. It also works surprisingly well in tandem with Alchemist buffs.

Relentless Glue can be a powerful tower but is usually overlooked, primarily because simply using both 0-1-3 and 1-3-0 glue together is around the same cost but more efficient. It is useful primarily when space or tower numbers are limited.



  • Relentless Glue is likely inspired by the third upgrade of the Glue Gunner's Specialty Building, the Glue Supply Depot.
  • In Bloons Tower Defense 6, this is the only way a Glue Gunner can glue Camo Bloons without support and abilities.
  • Relentless Glue, Double Gun (and by extension, Bloon Trap and XXXL Trap), and Robo Monkey are the only towers to be holding a pair of guns.
    • Strangely enough, Relentless Glue neither attacks faster nor attacks two separate projectiles per shot. It also doesn't have bonus popping power either.
  • The description for Relentless Glue is notorious for its poor grammar mistakes, as noted by a number of players. Grammatically speaking, it should be more like "Popped Bloons that were glued leave a blob of glue on the track."
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