Activate at least three Merfolk you control by tapping them, adding at least {2}{W}.
Cast Summon the School by paying {3}{W}, creating two 1/1 Merfolk Wizard creature tokens.
When the Merfolk Wizards enter the battlefield, Intruder Alarm triggers twice.
Resolve the first trigger, untapping all creatures.
Activate at least three Merfolk you control by tapping them, adding at least {2}{W}.
Resolve the second Intruder Alarm trigger, untapping all creatures.
If needed or desired, activate a Merfolk you control by tapping it, adding {1}.
Activate Summon the School by tapping four untapped Merfolk you control, returning Summon the School from your graveyard to your hand.
Repeat from step 2.
If you control four or more Merfolk that does not have summoning sickness, this combo nets infinite colored mana.

Infinite colored mana

Infinite creature tokens

Infinite ETB

Infinite magecraft triggers

Infinite mana creatures you control can produce

Infinite storm count

Infinite untap of creatures

Infinite untap of creatures you control

Summon the School

Intruder Alarm

Cryptolith Rite

Cast Summon the School for {3}{W}, creating four Merfolk creature tokens.
Activate Summon the School by tapping four untapped Merfolk, returning it to your hand.
Activate Phyrexian Altar by sacrificing a Merfolk token, adding one mana of any color.
Repeat step 3 an additional three times.
Repeat.

Infinite death triggers

Infinite LTB

Infinite sacrifice triggers

Phyrexian Altar

Anointed Procession

Cast Summon the School by paying {3}{W}, creating four 1/1 Merfolk Wizard creature tokens.
Activate Summon the School by tapping four Merfolk you control, returning it from your graveyard to your hand.
Activate Phyrexian Altar four times by sacrificing the Merfolk Wizards, adding {3}{W}.
Repeat.

Mondrak, Glory Dominus

Cast Summon the School for {3}{W}, creating four Merfolk creature tokens.
Activate Summon the School by tapping four untapped Merfolk, returning it to your hand.
Activate Ashnod's Altar by sacrificing a Merfolk token, adding {C}{C}.
Repeat step 3 an additional two times.
Activate Prismite for {2}, adding {W}.
Repeat.

Combos with "Summon the School"