Scary Deck (EDH / Commander)

Disclaimer

This is only nominally a 5-colors deck.
Although there are several ways to generate white mana (and green), I didn't want to play white because it would have pushed towards Esper. Which is like building a Sharuum deck, except that Sharuum isn't your commander, your mana base is worse and, well, your deck is stuffed with nigh-unplayable scarecrows.

Notable Combos

With Goblin Welder + Thornbite Staff and 2 artifact creatures, one in play and the other in the grave, one of them being:

• Wurmcoil Engine -> infinite tokens.
• Solemn Simulacrum -> infinite draws plus a bunch of lands.
• Treasure Keeper -> cast half of your deck.
• Duplicant -> exile all creatures (no longer in the deck).
• Baleful Strix -> infinite draws.
• Sphinx Summoner -> tutor whatever (fetch Patchwork Gnomes to inject whatever other creature in the loop).
• random scarecrow, with Reaper King in play -> destroy everything.

Scarecrone + Thornbite Staff with:

• Composite Golem -> infinite colored mana.
• Wurmcoil Engine + Ashnod's Altar/Krark-Clan Ironworks -> infinite mana and infinite tokens.
• Wingrattle Scarecrow + Ashnod's Altar/Krark-Clan Ironworks + any black creature -> infinite loop (if the black creature happens to be Reaper King, destroy everything).
  Scarecrone + Thornbite Staff can be swapped for Nim Deathmantle.

Metallic Mimic + Wingrattle Scarecrow + Ashnod's Altar/Krark-Clan Ironworks + any black creature -> infinite mana (if the black creature happens to be Reaper King, also destroy everything).

Marionette Master + Ashnod's Altar + Nim Deathmantle -> infinite tokens and infinite life loss.
Marionette Master + any infinite loop -> infinite life loss.

Staff of Domination + infinite mana -> do stupid things, then win the game somehow.

Coffin Queen + Thornbite Staff + Composite Golem -> infinite colored mana (not black).