Carrion Wall

Defender (This creature can't attack.)
{1}{B}: Regenerate Carrion Wall.

Death Pit Offering

When Death Pit Offering enters, sacrifice all creatures you control.
Creatures you control get +2/+2.

{3}{U}, {T}, Discard a card: Untap target creature and gain control of it until end of turn. That creature gains haste until end of turn.

Draw a card, then draw cards equal to the number of cards named Accumulated Knowledge in all graveyards.

{X}{U}, {T}, Discard two cards: Return X target creatures to their owners' hands.

Whenever a nontoken permanent is put into a player's graveyard from the battlefield, that player loses 1 life.

{4}: Return target creature card from a graveyard to its owner's hand. Any player may activate this ability but only as a sorcery.

{X}{B}, {T}, Discard two cards: Target player discards X cards at random.

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost.
Draw two cards.

Flying
{2}: Ribbon Snake loses flying until end of turn. Any player may activate this ability.

When a creature enters, sacrifice Monkey Cage and create X 2/2 green Monkey creature tokens, where X is that creature's mana value.

When Rishadan Footpad enters, each opponent sacrifices a permanent unless they pay {2}.

When Highway Robber enters, target opponent loses 2 life and you gain 2 life.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Cloud Sprite can block only creatures with flying.

{2}: Target creature gains flying until end of turn. Any player may activate this ability.

When Rishadan Cutpurse enters, each opponent sacrifices a permanent unless they pay {1}.

{U}: Tap target creature unless its controller pays {1}.

Destroy target nonblack creature. It can't be regenerated. You gain life equal to its toughness.

Whenever Shrouded Serpent attacks, defending player may pay {4}. If that player doesn't, Shrouded Serpent can't be blocked this turn.

Whenever Chambered Nautilus becomes blocked, you may draw a card.

Hazy Homunculus can't be blocked as long as defending player controls an untapped land.