Cast Gather Specimens by paying ({3} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) , causing all creatures that would be created under an opponent's control this turn to be created under you control instead.
Cast Fractured Identity by paying ({3} magic symbol) ({W} magic symbol) ({U} magic symbol) , targeting any permanent.
Holding priority, cast Naru Meha by paying ({2} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Naru Meha enters the battlefield, creating a copy of Fractured Identity, targeting Naru Meha.
Resolve the copy of Fractured Identity, exiling Naru Meha and creating a copy of Naru Meha for each opponent you have.
Put all but one Naru Meha token into your graveyard due to the legend rule.
The Naru Meha token(s) enter the battlefield, creating a copy of Fractured Identity targeting Naru Meha, and any other instants and/or sorceries on the stack.
Repeat from step 5.
You may also have the additional triggers target permanents your opponent control to exile them and create token copies of them.
Results
Exile any number of nonland permanents.
Infinite copies of any instants and/or sorceries on the stack.
Infinite copies of any nonland permanents on the battlefield.