Chthonian Nightmare enters the battlefield, it triggers, causing you to get ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) .
Activate
Chthonian Nightmare by paying ({E} magic symbol) ({E} magic symbol) ({E} magic symbol) , sacrificing a creature with mana value 3 or less and returning
Chthonian Nightmare from the battlefield to your hand, returning
Skullwinder from your graveyard to the battlefield.
When
Skullwinder enters the battlefield, it triggers, returning
Songs of the Damned from your graveyard to your hand and causing an opponent to return a card to their hand from their graveyard.