"Alakazam's brain continually grows, infinitely multiplying brain cells. This amazing brain gives this Pokémon an astoundingly high IQ of 5,000. It has a thorough memory of everything that has occurred in the world."
"Because it dedicates its energy entirely to its psychic powers, it maintains an unvarying meditative pose, floating in the air. A red organ that is said to emit psychic power manifests on Mega Alakazam's forehead."
Alakazam was brought back onto Lexi's team in Hoenn after she decided she needed to have strong Pokémon with her and also so she could utilize their ability to Mega Evolve. Unlike most other Pokémon, Alakazam was able to control itself upon becoming Mega Alakazam, which Steven stated was most likely due to the bond Lexi had with Tierno and therefore Alakazam.
Alakazam was kept in reserve following this, training at Lexi's Secret Base until he was needed.
Alakazam can outperform a super-computer. His IQ is said to be 5,000. His brain cells multiply continually, making his head too heavy to carry, therefore he uses his own powers to keep it up. He can memorize anything and never forgets what he learns, including if someone has been good or bad to him.