When Gixian Puppeteer dies, its second ability triggers, returning Doomed Necromancer from your graveyard to the battlefield.
Activate Lightning Greaves' equip ability by paying ({0} magic symbol) , attaching it to Dopomed Necromancer.
Activate Doomed Necromancer by paying ({B} magic symbol) , tapping and sacrificing it, returning Gixian Puppeteer from your graveyard to the battlefield.