If the creature is no longer a creature at the time it goes to the graveyard, you will still draw two cards if you controlled it at that time
That is a big part of why the card has remained so popular, because it connects the early Pokmon anime and game era with the more character-driven collecting habits that became especially strong during Sun & Moon
In that case, Hulking Metamorph simply enters the battlefield as a 7/7 (or 3/3) artifact creature
Consider what they discard, what they create, and how well they help the rest of your deck do what it already does best
What are you doing, Editor
Remember, too, that Atla has to be in play when the Eggs die for the ability to trigger, which makes her a huge removal magnet