BOEDS

The "Blimp Of Extreme Drilling Superiority" uses a powerful drill to burrow underground, punch through track placements and can even bore shortcuts for itself and other bloons, it also has glue immunity.

It travels fairly fast and has very high health, due to this they are quite uncommon to encounter.

Abilities
Tunnel: It can bore a hole underground, this slows it down significantly but once it's underground it can continue foward for a decent amount of time and be protected, but it must resurface to collect air (all of the armor and engine-ness gave little room for air) (This air is used for the jets to propel foward.) It then has to travel a fairly short distance above ground, but it can soon resume tunneling, when it is resurfacing and burrowing, it's pretty much immobile for a couple of seconds, allowing for damage to be delt.

Shortcut: some thin and weak walls can be drilled through completely, making a route for bloons and small/medium sized blimps to move through, however this significantly slows down the BOED and generally takes some time to do once the hole is made, it lasts for a long time, but over rounds it closes in, at first it stops medium blimps from passing, then small things like moabs can't pass, until finally standard bloons can't get through the gap. Unfortunately, if it in the process of repairing, another BOED can re-open it, and it's quicker to bore through if it has repaired less.

Pummel: If a tower is on the path, it can deal extreme damage to it with the drill.

Neutralise: The goo leaking off exists to counter glue-type things and remove it very quickly (so you can forget about trying to hit it with glue melt it when it starts boring underground.)