Hello folks !
I was on the Pomeg Glitch Bulbapedia page and it says
If the player has only an Egg in his or her party with the Pokémon affected, the Egg (or rather, the Pokémon that would be inside) can be forced into battle by following the same steps, but putting the Egg at the head of the party. The Egg will have the same stats it would have upon hatching, as well as all of the moves. This allows it to battle as if it were a normal Pokémon. When battling with an Egg, the sprite of the Pokémon within the Egg is displayed; however, there may be irregularity in the coloring of the Pokémon. This may be because the game is reading the backsprite of the Pokémon within the Egg and the color palette of the Egg itself.
An Egg that battles can gain experience in this way, and with patience, level up, learn moves, and even evolve before hatching. However when it hatches the level is set to 5, EVs reset to zero and all EXP gained in the Egg is removed. This allows level 5 versions of high-evolutionary Pokémon such as Tyranitar or Dragonite to be obtainable, it also allows otherwise illegal moveset/level combinations, such as a level 5 Staryu with Hydro Pump.
If I understood well, this means that we can get this damn level 9 and under Tyranitar, Dragonite and the likes simply by transferring them games over games, and trade them for level 100 shiny Milotic for example.
Is it realisable, or is the Pokémon like Level 5 Tyranitar considered as a hack ?