Gardevoir are often called the embrace pokemon, and many are known to be affectionate towards their trainers. This is not the sort of embrace which gives them this title. The embrace which gives Gardevoir their title is a stellar yet terrifying thing, an embrace so tight not even light can escape, an embrace not used on their trainer, but on their trainer's enemies in dire situations: a miniature black hole.
When truly lightless areas were discovered in distant space, they were properly likened to this attack, and humanity wondered how Gardevoir were capable of creating something so similar to a cosmic phenomenon. Some theorized that Ralts themselves were made from the same material as the stars, and that they are somehow able to channel their final phase, a black hole, into an attack once they evolve to their most powerful form. This theory was rejected on the grounds that the Ralts line is psychic-type, not fire-type, but this led to further questions on what precisely is meant by a "psychic" pokemon.
The currently accepted theory of Gardevoir's black hole redefines the psychic type itself, suggesting that "psychic" attacks rely not on control of the enemy's mind, but on the manipulation of light and gravity to confuse and wound the defending pokemon. They no more perform psychic techniques than a street illusionist performs magic, but like them use a variety of expert skills to make people think they can bend the laws of reality. If this is the case, Gardevoir's black hole technique is the ultimate psychic attack, for it relies on command of both gravity and light to create a power so strong it needs no trickery to work, for it can devour all.
Or perhaps there is no black hole to begin with, just one remarkable illusion.