CardName: Perilous Zendikar
Cost:
Type: Legendary Land
Pow/Tgh: /
Rules Text: {T}: Add {1} to your mana pool.
{1}{R}, {T}: Look at the top five cards of your library. You
may cast an instant from among them targeting a creature
attacking you or a planeswalker you control. Put the rest on
the bottom of your library in any order.
Flavour Text:
Set/Rarity: Multiverse Design Challenge None
Perilous Zendikar
Legendary Land
: Add to your mana pool.
, : Look at the top five cards of your library. You may cast an instant from among them targeting a creature attacking you or a planeswalker you control. Put the rest on the bottom of your library in any order.
: Add 
to your mana pool.
,
See Challenge # 120.
This is slightly too wordy but I wanted to try to capture the "trap" flavour of Zendikar. Hence I went with R, even though Soul of Zendikar is G.