Corrosive Glue

Corrosive Glue turns the glue into a weak damage-over-time effect: glued Bloons take 1 damage every 2 seconds for as long as the glue lasts. It also lets the Glue Gunner target and glue MOAB-class Bloons. Blimps take the damage over time but are not slowed unless you also have MOAB Glue. Corrosive glue can overwrite glue from other, weaker Glue Gunners.

When to buy it

As 2-1-0 or 2-2-0 it is a decent early support for high-health rounds like 26 and 35, chipping away at Zebras and Rainbows while they crawl. It is much weaker against big clumps of small Bloons (rounds 27 and 36) and misses a lot on Expert maps, so treat it as a helper, not a carry.

It is the step you need for Bloon Dissolver and the rest of the top path. As a crosspath it matters most for Glue Strike and Glue Storm: 2-4-0 lets the ability glue every Bloon on screen with damage over time, which is a strong trick in Races against non-Freeplay rounds. On MOAB Glue, Relentless Glue and Super Glue it adds bonus MOAB damage per tick, but the extra pierce from the middle path is almost always the better pick.

Is it worth it?

Buy it on the way to Bloon Dissolver or for a Race-style Glue Strike. On Glue Hose, Stronger Glue is usually the better crosspath, and on the bottom path tier 3+ builds it is rarely worth it.