Quote Originally Posted by Dark Sage View Post
How come? Because Dugtrio is three Pokemon combined?

It isn't the only Pokemon where evolution involves more than one Pokemon combining. Slowpoke and Cloyster do it too (to become either Slowbro OR Slowking). Also, according to PokeDex entries, Metang is a combination of two Beldum, while Metagross is a combination of two Metang.

I guess you could compare this to a symbiotic relationship, if you wanted to use real-life biological terms.
Magneton is ALSO a combined Pokemon. It is just three Magnemite attached to each other to form a pyramid like shape.