Newtron

Sonic 1 official artwork.

Sonic 2 8-bit official artwork.

Newtron, called Meleon (メレオン) in the Japanese manual, is one of Doctor Ivo "Eggman" Robotnik's badniks that appears in several of the early Sonic games. They come in two flavours, blue and green. The robotic chameleons pop up in:

• Sonic the Hedgehog (16-bit), in Green Hill Zone - First and only 16-bit portrayal (1991).
• Sonic the Hedgehog (8-bit), in Jungle Zone - First 8-bit appearence (1991).
• Sonic the Hedgehog 2 (8-bit), in Underground Zone, Sky High Zone, Green Hills Zone - (1992).
• Sonic the Hedgehog 4, in Splash Hill Zone - (2010).

"Green" Newtrons are by far the most common. They typically cling to rocky walls, invisible, until Sonic gets close. Then the sneaky machines de-cloak just long enough to fire an energy ball in the hedgehog's direction, before fading back into the background. Once vanished, Newtrons cannot be destroyed even if Sonic spin attacks where you know they are hiding; if they're invisible, the chance for points is lost.

"Blue" Newtrons are seen in only one Zone, the original 16-bit Green Hill. Like their green counterparts, they remain invisible until Sonic walks close by, but instead of firing an energy bolt they drop off the wall and transform into a ground-skimming missile! Given that the badniks persist in this form - rather than turning invisible again later - they are much easier to destroy than the green Newtrons.