Radiant Lotus (6)

Artifact

(Tap), sacrifice any number of artifacts: Choose a color. Target player adds 3 mana of the chosen color for each artifact sacrificed this way.

...

Okay, hear me out:

• Activate this card, sacrificing itself, Myr Retriever, Scrap Trawler, a 1 mana artifact, and Mox opal, grabbing 15 red mana. Don't forget to activate Mox Opal for 1 mana of any color, so you actually get 16 mana.

• 1 mana artifact goes on the stack after paying its cost. 15 mana left.

• Scrap Trawler grabs back Myr Retriever, itself, and Opal, while Myr Retriever grabs back the Lotus.

• Replay all your cards, except the 1 mana artifacg (6+3+2+0=11)

• You are now back where you were originally, except you have 4 extra mana.

WE HAVE A NEW KCI!