Torpor Orb

Creatures entering don't cause abilities to trigger.

Tend the Pests

As an additional cost to cast this spell, sacrifice a creature.
Create X 1/1 black and green Pest creature tokens with "When this token dies, you gain 1 life," where X is the sacrificed creature's power.

Phyrexian Dreadnought

Trample
When this creature enters, sacrifice it unless you sacrifice any number of creatures with total power 12 or greater.

The One Ring

Indestructible
When The One Ring enters, if you cast it, you gain protection from everything until your next turn.
At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring.
{T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

Seedtime

Cast this spell only during your turn.
Take an extra turn after this one if an opponent cast a blue spell this turn.

Mercy Killing

Target creature's controller sacrifices it, then creates X 1/1 green and white Elf Warrior creature tokens, where X is that creature's power.

Berserk

Cast this spell only before the combat damage step.
Target creature gains trample and gets +X/+0 until end of turn, where X is its power. At the beginning of the next end step, destroy that creature if it attacked this turn.