The Shapeshifting Invader (Cuttlefish) is an invader that appeared in Space Invaders Part II. It has the special ability to grow and shrink, making it harder or easier to hit with a missile.
The Shapeshifting Invader has a very similar appearance to that of the Small Invader. As it has a triangular head and 2 eyes. However, the Shapeshifting Invader only has 2 appendages and no visible mouth.
It was revealed to look like this by Toshihiro Nishikado for the game's 40th Anniversary, though it has had different appearances in later games like the other classic invaders. This version is more reliable as it is the official concept art for the original games. It is strange how the Shapeshifting Invader has four, tentacles while it's original sprite has only two that occasionally shrink. It is not completely known whether or not this art was meant to depict this invader, but it can be assumed as such by process of elimination and how the in-game sprite was shown alongside it.
The Shapeshifting Invader can grow to approximately the same size as the Small Invader and shrink to about half it's original size, making it harder for the player to shoot it down.