Things You'll Need
Instructions
Visit an underground location in "Pokemon Pearl" or "Pokemon Platinum."
Dig for fossils until you find a shield fossil.
Take the shield fossil to Oreburgh Mining Museum and request the attendant to revive the fossil. The fossil will turn into a Shieldon.
Start "Pokemon Pearl" or "Pokemon Platinum" on one Nintendo DS and "Pokemon HeartGold" on the other.
On both games, proceed to the Pokemon Center and talk to the receptionist at the middle desk. This will grant you access to the Union Room.
Use the DS playing "Pokemon Pearl" or "Pokemon Platinum" and have your character approach the character from "Pokemon HeartGold."
Converse with the character from "HeartGold" and request a trade.
Send the Shieldon to the "HeartGold" game in exchange for any other Pokemon from the "HeartGold" game. Once the trade is complete, you can use the Shieldon in "HeartGold."