More Than Meets the Eye is an alternate casting cost found on Transformers cards (from the Universes Beyond Transformers set). These are double-faced cards where the front face is a robot character and the back is a vehicle. The ability lets you cast the card as its back face (the converted/vehicle side) by paying the More Than Meets the Eye cost instead of the front face's mana cost.
The common confusion: this is just an alternative cost to cast the spell, not a transform mechanic. You're choosing which face to cast from your hand, and once it resolves it can later "convert" between faces if it has a convert ability. You can't use More Than Meets the Eye for cards already on the battlefield—it's strictly for casting from hand (or wherever you're allowed to cast it).
In Commander, these cards are rare since the set is small, but they offer flexibility: cast cheaply as a vehicle early, or pay full price for the robot's stronger creature side later.