Shadow is indeed The Ultimate Lifeform. Even at an infantile state he has a strong grip that can break steel. Yet giggles adorably in the face of violence.
@ChardonnayBloo Impossible, we see the creation of Shadow in his game Shadow the Hedgehog, and he was already the correct age while it was happening. One of the eyewitnesses, the GUN Commander, recalled it as a monster being created.
Technically @/Timmymyboy is correct, and 06 also shows that Shadow (being the artificial monster he is) doesn't age. But who cares tbh, this comic's cute and that's all that really matters that much.