Another Pokemon fanart. XP
After defeating all 16 gym leaders in Pokemon HeartGold or SoulSilver, you will have the opportunity to battle them at certain time on a certain day, after you register their Pokegear numbers. They will stay in the Fighting Dojo until you battle them.
Even if it's a week late, they will still be there. I lol'd.
In other news, meet Aidan, my Typhlosion! :3