Activate Blistercoil Weird by tapping it, adding {U} that can only be spent to cast an instant or sorcery spell, or to gain a Class level.
Cast Mystic Speculaiton with buyback by paying {U}.
Blistercoil Weird triggers, and Sorcerer Class's third ability triggers if it it level three.
Resolve the Blistercoil Weird trigger, giving itself +1/+1 until end of turn and untapping it.
Resolve the Sorcerer Class trigger, if applicable, dealing damage to each opponent equal to the number of instants and sorceries you've cast this turn.
Resolve Mystic Speculation, causing you to scry 3 and return Mystic Speculation to your hand.
Repeat.

Infinite damage

Infinitely large creature until end of turn

Infinite magecraft triggers

Infinite scry

Infinite storm count

Blistercoil Weird

Mystic Speculation

Memory Crystal

Sorcerer Class

Activate Blistercoil Weird by tapping it, adding {U}.
Cast Mystic Speculaiton with buyback by paying {U}.
Blistercoil Weird triggers, giving itself +1/+1 until end of turn and untapping it.
Resolve Mystic Speculation, causing you to scry 3 and return Mystic Speculation to your hand.
Repeat.

Paradise Mantle

Activate Blistercoil Weird using the ability granted to it by Elemental Mastery by tapping it, creating a number of creature tokens.
When the token(s) enter, Spiritcall Enthusiast triggers, causing it to become prepared.
Activate Phyrexian Altar by sacrificing a creature token, adding {W}.
Cast a copy of Scrollboost by paying {W}, targeting any valid target(s).
Blistercoil Weird triggers, giving it +1/+1 until end of turn and untapping it.
Resolve Scrollboost, giving up to two creatures +2/+2 each until end of turn.
Repeat.

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite death triggers

Infinitely large creatures you control until end of turn

Infinite colored mana

Infinite creature tokens that are infinitely large

Infinite creature tokens with haste

Spiritcall Enthusiast // Scrollboost

Elemental Mastery

Cryptolith Rite

Combos with "Blistercoil Weird"