Imp Dropper Balloon

Imp Dropper Balloon is a hot air balloon with a zombie pilot and three Imps. The pilot drops an Imp each 300 dps (15 nds) of damage received. It appears in Modern Day in Plants vs. Zombies 2.

It is a special flying unit. The balloon can float over all plants, even Tall-nuts, but still has to pause to raise altitude. Blovers cannot blow this unit away out of the screen but instead just send it back 3 tiles. Hurrikales also have a similar interaction.

Origins and appearance
A hot air balloon with a zombie pilot wearing a traditional pilot uniform and three regular Imps. The hot air balloon has a drawn face like that of a Balloon Zombie. The appearance is based on the unpublished redesign of Air Bomb Zombie.

Overview
Imp Dropper Balloon absorbs 1200 damage per shot (60 normal damage shots). Appearance changes upon absorption of 300 dps/15 nds (also drops the 1st Imp), 600 dps/30 nds (also drops the 2nd Imp), 900 dps/45 nds (also drops the 3rd Imp) before dying at 1200 dps/60 nds.

Strategy
Like Balloon Zombie, he will temporarily stop moving forward to raise altitude when flying over a plant, a fact which can be used to stall it. This trait also applies to Jetpack Zombie, Bug Zombie and Blastronaut Zombie.

Technically, Imps aren't there with the balloon and are individually spawned as the balloon takes damage, so once the balloon gets very heavy damage from instant kills or heavy projectiles, it is possible for more than one Imp to drop at once.

Instant kills like Cherry Bombs can take out the balloon in one hit, if the balloon is at full health this will cause three Imps to drop simultaneously so plan accordingly.