Goblin Shortcutter

When this creature enters, target creature can't block this turn.

Goblin War Paint

Enchant creature
Enchanted creature gets +2/+2 and has haste.

Iona, Shield of Emeria

Flying
As Iona enters, choose a color.
Your opponents can't cast spells of the chosen color.

Hellfire Mongrel

At the beginning of each opponent's upkeep, if that player has two or fewer cards in hand, this creature deals 2 damage to that player.

Hellkite Charger

Flying, haste
Whenever this creature attacks, you may pay {5}{R}{R}. If you do, untap all attacking creatures and after this phase, there is an additional combat phase.

Highland Berserker

Whenever this creature or another Ally you control enters, you may have Ally creatures you control gain first strike until end of turn.

Inferno Trap

If you've been dealt damage by two or more creatures this turn, you may pay {R} rather than pay this spell's mana cost.
Inferno Trap deals 4 damage to target creature.

Kazuul Warlord

Whenever this creature or another Ally you control enters, you may put a +1/+1 counter on each Ally creature you control.

Lavaball Trap

If an opponent had two or more lands enter the battlefield under their control this turn, you may pay {3}{R}{R} rather than pay this spell's mana cost.
Destroy two target lands. Lavaball Trap deals 4 damage to each creature.

Magma Rift

As an additional cost to cast this spell, sacrifice a land.
Magma Rift deals 5 damage to target creature.

Mark of Mutiny

Gain control of target creature until end of turn. Put a +1/+1 counter on it and untap it. That creature gains haste until end of turn. (It can attack and {T} this turn.)

Molten Ravager

{R}: This creature gets +1/+0 until end of turn.

Murasa Pyromancer

Whenever this creature or another Ally you control enters, you may have this creature deal damage to target creature equal to the number of Allies you control.

Journey to Nowhere

When this enchantment enters, exile target creature.
When this enchantment leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Obsidian Fireheart

{1}{R}{R}: Put a blaze counter on target land without a blaze counter on it. For as long as that land has a blaze counter on it, it has "At the beginning of your upkeep, this land deals 1 damage to you." (The land continues to burn after this creature has left the battlefield.)

Plated Geopede

First strike
Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Zendikar