Activate Cormela by paying ({1} magic symbol) and tapping it, adding ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) that can only be spent to cast instant or sorcery spells.
When Cormela dies, it triggers, returning Exhume from your graveyard to your hand.
Cast Exhume by paying ({1} magic symbol) ({B} magic symbol) , causing each player to return a creature card from their graveyard to the battlefield, with you choosing to return Cormela.
Repeat.
Results
Infinite blue mana that can only be spent to cast instant and sorcery spells.
Infinite death triggers.
Infinite ETB.
Infinite LTB.
Infinite magecraft triggers.
Infinite red mana that can only be spent to cast instant and sorcery spells.