Declare Fear of Missing Out as an attacker, triggering its ability, causing you to untap it and to get an additional combat phase after this one.
Deal combat damage to an opponent using Fear of Missing Out, triggering Impostor Syndrome, creating a token copy of Fear of Missing Out that isn't legendary.
When the Fear of Missing Out token enters, it triggers, causing you to rummage
During your next combat phase, declare Fear of Missing Out and the Fear of Missing Out token as attackers.
The Fear of Missing Out token triggers, causing you to untap the nontoken Fear of Missing Out and to get an additional combat phase after this one.
Repeat from step 2.
This cunning sequence uses Fear of Missing Out as the engine of an ever-multiplying combat loop, fueled by Fires of Yavimaya granting your team haste so they can charge straight into battle the turn they arrive. Every time Fear of Missing Out connects with an opponent, Impostor Syndrome steps in to forge a fresh token copy, cleverly bypassing the legend rule while triggering the original's entry effects over and over. As these token copies enter and attack, they repeatedly untap the original Fear of Missing Out and grant you endless additional combat phases, generating an overwhelming storm of combat damage, card draw, and discard triggers.