Mythos of Vadrok

Mythos of Vadrok deals 5 damage divided as you choose among any number of target creatures and/or planeswalkers. If {W}{U} was spent to cast this spell, until your next turn, those permanents can't attack or block and their activated abilities can't be activated.

Cat Bird

Vadrok, Apex of Thunder

Mutate {1}{W/U}{R}{R} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying, first strike
Whenever this creature mutates, you may cast target noncreature card with mana value 3 or less from your graveyard without paying its mana cost.

Dinosaur Cat

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Skycat Sovereign

Flying
Skycat Sovereign gets +1/+1 for each other creature you control with flying.
{2}{W}{U}: Create a 1/1 white Cat Bird creature token with flying.

Cubwarden

Mutate {2}{W}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Lifelink
Whenever this creature mutates, create two 1/1 white Cat creature tokens with lifelink.

Regal Leosaur

Mutate {1}{R/W}{R/W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, other creatures you control get +2/+1 until end of turn.

Gavi, Nest Warden

You may pay {0} rather than pay the cycling cost of the first card you cycle each turn.
Whenever you draw your second card each turn, create a 2/2 red and white Dinosaur Cat creature token.