Cast this spell only during the declare blockers step.
For each creature attacking you or a planeswalker you control, create a token that's a copy of that creature and that's blocking that creature. Exile those tokens at end of combat.

Flying
Vigilance (Attacking doesn't cause this creature to tap.)

Buyback (You may pay an additional as you cast this spell. If you do, put this card into your hand as it resolves.)
Counter target spell with mana value X.

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, its controller loses 2 life and you gain 2 life.

You may sacrifice four Eldrazi Spawn rather than pay this spell's mana cost.
Annihilator 1 (Whenever this creature attacks, defending player sacrifices a permanent of their choice.)

When this creature enters, if you have four or more creature cards in your graveyard, you may return target creature card from your graveyard to your hand.

Whenever another creature you control enters, creatures you control get +1/+1 until end of turn.

Creature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a creature spell pays for or one mana of that creature's color.)
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

As long as you've drawn two or more cards this turn, this creature has double strike.

Flying
Whirlwind — When this creature enters, return up to one other target creature to its owner's hand.

Target player discards X cards at random.

First strike
As this creature enters, you may put a name sticker on it.
This creature has protection from names that start with the same letter as a name sticker on it.

Enchant creature
Enchanted creature gets +3/+3.
At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.

: Add one mana of any color.
: Exile target card from a graveyard.
You may cast Dinosaur creature spells from among cards you own exiled with this creature. If you cast a spell this way, that creature enters with a finality counter on it. (If a creature with a finality counter on it would die, exile it instead.)

Firebending 2
During your turn, each non-Lesson instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost. (You may cast a card from your graveyard for its flashback cost. Then exile it.)
During your turn, each Lesson card in your graveyard has flashback .

Menace
Modular 2 (This creature enters with two +1/+1 counters on it. When it dies, you may put its +1/+1 counters on target artifact creature.)
Whenever you cast a spell other than your first spell each turn, put a +1/+1 counter on this creature.

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

If was spent to cast this spell, return up to one target creature to its owner's hand. If was spent to cast this spell, target player reveals their hand, you choose a nonland card from it, then that player discards that card. (Do both if was spent.)

Devour 1 (As this creature enters, you may sacrifice any number of creatures. It enters with that many +1/+1 counters on it.)
When this creature enters, it deals 3 damage to each creature.

Descend 4 — As long as there are four or more permanent cards in your graveyard, Akawalli gets +2/+2 and has trample.
Descend 8 — As long as there are eight or more permanent cards in your graveyard, Akawalli gets an additional +2/+2 and can't be blocked by more than one creature.