Megaton's Fate | Dualcaster Mage | Lilysplash Mentor (and one other card)

Artifact that is Indestructible

Cards

({6} magic symbol) ({G} magic symbol) ({U} magic symbol) ({R} magic symbol) available.

Cast
Megaton's Fate by paying ({5} magic symbol) ({R} magic symbol) , targeting the indestructible artifact.
Holding priority, activate
Lilysplash Mentor by paying ({1} magic symbol) ({G} magic symbol) ({U} magic symbol) , blinking
Dualcaster Mage.
When
Dualcaster Mage enters the battlefield, it triggers, copying
Megaton's Fate, with the copy targeting the indestructible artifact.
Resolve the copy of
Megaton's Fate, failing to destroy the artifact due to it being indestructible, and creating four Treasure tokens.
Activate three Treasure tokens by tapping and sacrificing them, adding ({1} magic symbol) ({G} magic symbol) ({U} magic symbol) .
Repeat from step 2.

This combo has been estimated to be Exhibition (Bracket 1+).