Activate Altar of Dementia by sacrificing Skullwinder.
When Skullwinder dies, Mortuary triggers, putting Skullwinder on top of your library from your graveyard.
Resolve the Altar of Dementia ability, causing target player to mill cards equal to Skullwinder's power.
Cast Hit the Mother Lode by paying ({4} magic symbol) ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) , exiling Skullwinder from the top of your library and casting it without paying its mana cost, and creating seven tapped Treasure artifact tokens.
When Skullwinder and the Treasures enter the battlefield, Amulet of Vigor triggers seven times and Skullwinder triggers once.
Resolve all Amulet of Vigor triggers, untapping the Treasures.
Resolve the Skullwinder trigger, returning Hit the Mother Lode from your graveyard to your hand, and causing an opponent to return a card from their graveyard to their hand.