When Ogre Chitterlord dies, Nim Deathmantle triggers, causing you to pay ({4} magic symbol) to return Ogre Chitterlord from your graveyard to the battlefield, and attach Nim Deathmantle to it.
When Ogre Chitterlord enters the battlefield, it triggers, creating two 1/1 Rat creature tokens and giving Rats you control +2/+0 until end of turn if you control five or more Rats.
Activate Ashnod's Altar by sacrificing the Rat, adding ({C} magic symbol) ({C} magic symbol) .
Repeat.
Results
Infinite colorless mana.
Infinite creature tokens.
Infinite death triggers.
Infinite ETB.
Infinite LTB.
Infinitely powerful Rats you control until end of turn.