Whenever a creature you control enters, you gain 1 life.

To solve — You've gained 5 or more life this turn. (If unsolved, solve at the beginning of your end step.)

Solved — Sacrifice this Case: Creature cards in your graveyard gain "You may cast this card from your graveyard" until end of turn.

Destroy all non-Giant creatures. (Then exile this card. You may cast the creature later from exile.)

Flash
When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.
Cycling

Untapped creatures you control get +0/+2.

Flying
As long as this creature is untapped, it gets +0/+2.

When this creature enters, create a Food token.
Whenever you gain life for the first time during each of your turns, create a 1/1 white Cat creature token.

Each player chooses from among the permanents they control an artifact, a creature, an enchantment, and a land, then sacrifices the rest.

Vigilance
When this creature enters, each player chooses an artifact, a creature, an enchantment, and a planeswalker from among the nonland permanents they control, then sacrifices the rest.

Tap five untapped Soldiers you control: Exile target creature.

Tap two untapped Soldiers you control: This creature deals 2 damage to target attacking or blocking creature.

Destroy all lands or all creatures. Creatures destroyed this way can't be regenerated.

Flash
, Sacrifice this creature: Destroy target artifact or enchantment.

Enchant creature
Enchanted creature has vigilance and "At the beginning of your end step, create a 1/1 white Human creature token."

Whenever you cast a noncreature spell, this creature gains indestructible until end of turn.

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

( can be paid with either or 2 life.)
Defender
When this creature dies during combat, it deals 6 damage to each creature it blocked this combat.

When this creature enters, you gain 3 life.

Enchant creature
Enchanted creature can't attack or block.
When a Vehicle you control attacks, exile enchanted creature.

Vigilance
When this creature enters, destroy up to one target nonland permanent. Its controller creates a 3/3 colorless Golem artifact creature token.
When this creature dies, return target artifact or enchantment card from your graveyard to your hand.

When this creature enters, target creature gets +2/+0 and gains first strike until end of turn.

Flanking
Other creatures you control with flanking have flanking. (Each instance of flanking triggers separately.)

Flying
Whenever this creature attacks, each attacking Human gains flying until end of turn.