The Invader UFOs are the main air troops from the Invader Army. It is composed by a strange flying UFO crewed by a Drone. It can shoot different types of munition varying in damage, color and velocity. They aren't well armored, so they compensate this by flying in formations of six.
|Invader UFO: The original variant.|
|Ravenous Invader UFO: A wingless Ravenous Invader operates this UFO, which has a bit more armor than the original. They fire precise shots at the enemy. Appears in Metal Slug Attack.|
- Their flying patterns closely resembles those of lesser enemies from the Gradius series.
- Before its official name reveal in Metal Slug Defense, these were known as a "VFO" which stands for "Venusian Flying Object".