From ErfWiki

Proposed Canon

Some types of Units have Breath Weapon Natural Ability, which allows them to release a short/medium range attack against enemies before or instead of melee combat. Despite its name, the attack is not always released from the Unit's mouth (e.g. Yellow Dwagons).

Known Units

List of known Units with a Breath Weapon attack:

• Dwagons - type of attack depends on the Dwagon's color
  • Red_dwagon - fire
  • Blue_dwagon - lightning
  • Brown_dwagon - smoke
  • Green_dwagon - poison? gas
  • Pink_dwagon - pink bubblegum
  • Purple_dwagon - sonic
  • Yellow_dwagon - acidic battlecrap
• Sourmanders - presumably acidic spit

Speculation