Magnetran

Magnetran, the Magnetic Pole Pokemon. Electric/Steel-type.
This Pokemon lives in cold environments and avoids humans. It's body constantly emits a powerful magnetic field, causing headaches and numbness in some people and Pokemon. When threatened it can intensify the gravity in it's local area.
Magnetran has a brand-new ability: Magnetic Field. This ability causes Steel-types to become trapped and unable to flee. If Electric Terrain comes into effect, this Pokemon levitates on the magnetism, negating Ground-moves and grounded effects.
Further, Magnetran has access to several Steel and Electric moves, including Iron Head, Flash Cannon, Magnetic Flux and the new Steel-type trapping move; Magnetizing Wave. This move deals damage whilst preventing the opponent from switching.

Magnetran was inspired by the idea of a reverse-Heatran. Heatran represents the Eath's core and the fact it is extremely hot and made of metal. Magnetran represents the earth's Magnetic Poles and gravity effects.
I nearly called it Voltran but I didn't want to be so close to Voltron. Magentran seemed the natural next closest - I wanted to keep the 'tran' suffix to let it tie into Heatran.
The lines and markings on the body are symvols used in drawing circuity diagram. The long lines on it's side represent a batter, the circles on it's jaw are a switch that can open and close (like the moyth) and it's teeth are resistors. It's a silly idea but I kinda love it in a way.

Honestly though, I like that Heatran is the one Legendary with no connection to any other. I hope they do more of those.