Attack with Triton Shorestalker and when it isn't blocked, cast Sakashima's Student's for it's ninjutsu cost, paying {1}{U} and returning Triton Shorestalker to hand.
Have Sakashima's Student enter the battlefield as a copy of Medomai the Ageless and deal combat damage, gaining you an extra turn.
During your second main phase, cast Triton Shorestalker for {U}.
Return Sakashima's Student to your hand with Aegis Automaton for {4}{W}.
Pass the turn to yourself and repeat.

Infinite turns

Lock

Medomai the Ageless

Sakashima's Student

Triton Shorestalker

Mirror Gallery

Aegis Automaton

Attack with Triton Shorestalker and when it isn't blocked, cast Sakashima's Student's for it's ninjutsu cost, paying {1}{U} and returning Triton Shorestalker to hand.
Have Sakashima's Student enter the battlefield as a copy of Medomai the Ageless and deal combat damage, gaining you an extra turn.
During your second main phase, cast Triton Shorestalker for {U}.
Return Sakashima's Student to your hand with Erratic Portal for {1}.
Pass the turn to yourself and repeat.

Erratic Portal

Declare Triton Shorestalker as an attacker.
During the declare blockers phase, when you recieve priority, activate Sakashima's Student's Ninjutsu ability by paying {1}{U} and returning Triton Shorestalker from the battlefield to your hand, putting Sakashima's Student from your hand onto the battlefield tapped and attacking as a copy of Medomai.
Deal combat damage with Sakashima's Student, causing you to take an additional turn after this one.
Cast Triton Shorestalker by paying {U}.
Equilibrium triggers, causing you to pay {1} to return Sakashima's Student from the battlefield to your hand.
Pass the turn.
Repeat.

Equilibrium

Attack with Triton Shorestalker and when it isn't blocked, cast Sakashima's Student's for it's ninjutsu cost, paying {1}{U} and returning Triton Shorestalker to hand.
Have Sakashima's Student enter the battlefield as a copy of Medomai the Ageless and deal combat damage, gaining you an extra turn.
During your second main phase, cast Triton Shorestalker for {U}.
Return Sakashima's Student to your hand with Crystal Shard for {U}.
Pass the turn to yourself and repeat.

Combos with "Triton Shorestalker"