Ovika, Enigma Goliath | Cloudstone Curio | Invasion of Segovia // Caetus, Sea Tyrant of Segovia

Cards

Sea Tyrant of Segovia.
You have a noncreature, nonartifact permanent card in hand that can be cast using only red mana.
You control a nontoken, noncreature, nonartifact permanent that shares a card type with the card in your hand, and that can be cast using only red mana.
You are able to cast the card in hand.
If the card on the battlefield has a larger mana value than the card in hand, you either have enough mana or control enough creatures to pay for the difference.

Cast the card from your hand by paying its mana cost reduced by the number of other creatures you tap as you cast it.
Ovika triggers, creating a number of 1/1 Phyrexian Goblin creature tokens with haste equal to that spell's mana value.
When the Phyrexian Goblins enter the battlefield,
Cloudstone Curio triggers that many times.
Resolve all
Cloudstone Curio triggers, choosing not to return anything to your hand from the battlefield.
Resolve the permanent spell cast in step 1.
When the permanent enters the battlefield,
Cloudstone Curio triggers, returning another nontoken, noncreature, nonartifact permanent that shares a type with the permanent that entered the battlefield to your hand from the battlefield.
Repeat.

This combo has been estimated to be Exhibition (Bracket 1+).