When two or more independent Mecha can combine to make another, larger mecha. It can be a decent way to hide a really big robot in plain sight, by breaking it up into pieces. After the merge (accompanied by the stock Transformation Sequence), the new mecha will have powers and abilities greater than the sum of its parts. Combining Mecha are frequently a metaphor for Team Spirit and/or The Power of Friendship because of this. It's common to find these in the same places as Transforming Mecha -- indeed there are many that can do both. A frequent source of Technology Porn.