Corrosive Glue

Corrosive Glue is the Glue Gunner's level 4 upgrade in BTD4, costing $255 on easy, $300 on medium, and $325 on hard, and the 2nd in the 1st Path in BTD5. It is a monkey wearing a loose purple Haz-mat suit and goggles with a yellow glue container on its back. The glue pops one layer of bloon every 2 seconds. Ceramic bloons aren't slowed down by corrosive glue, but it will still harm them. The Corrosive Glue upgrade does not affect M.O.A.B. class bloons. It can also pop lead bloons, which is an effective way of getting rid of them accurately in the early levels.

Trivia

 * In BTD4, if you upgrade a Glue Gunner to Corrosive Glue during a round, all of the bloons that the Glue Gunner already glued in that round will have corrosive glue.
 * The artwork of the Glue Gunner with Corrosive Glue in Bloons Tower Defense 5 has green glue dripping from his gun even though he shoots yellow glue, however the Bloon Liquefier shows yellow glue even though he shoots green glue.
 * This is the only upgrade for the Glue Gunner in Bloons TD 5 that has yellow corrosive glue.
 * Corrosive Glue pops slightly faster than the speed of which regen bloons regenerate which allows it to still pop them.
 * This can destroy a Rainbow Bloon on any beginner track, and a Ceramic Bloon on any beginner track in Bloons TD 4 iOS.