Kadabra and Alakazam are Psychic-type Pokemon introduced in the first generation "Red," "Blue" and "Yellow" games. Both possess high Speed and Special Attack stats and frail HP and Defense stats. In battle, Kadabra and Alakazam make excellent special sweepers due to their superb offences and large movepool, which includes such attacks as "Psychic," "Shadow Ball," "Energy Ball" and "Charge Beam." They can also take on support roles with attacks such as "Thunder Wave," "Reflect," "Light Screen" and "Trick." In the fourth generation "Diamond," "Pearl," "Platinum," "HeartGold" and "SoulSilver" games, players can evolve Kadabra into Alakazam without trading, by exploiting a useful glitch on the GTS.
Enter the Global Trade Station in Jubilife City if you are playing "Diamond," "Pearl" or "Platinum," or in Goldenrod City west of the Radio Tower if you are playing "HeartGold" or "SoulSilver." Talk to the receptionist and connect to the global trade network.
Offer to trade Kadabra for an impossible Pokemon, such as a level 1 Ho-oh, and then disconnect from the network.
Talk to the receptionist again and reconnect to the network. Withdraw your trade offer and Kadabra will evolve into Alakazam, rejoining your party in the process.