"Wanderwine Prophets" is a 4/4 blue merfolk wizard printed as a rare for the Magic the Gathering expansion set known as "Lorwyn." This is one of the cards in the Lorwyn block that encourage players to build around a theme of creatures. With respect to the Wanderwine Prophets, players are encouraged to build around theme of merfolk. In this respect, Wanderwine Prophets seems to be good in a control deck with plenty of merfolk creatures.
The converted mana cost for Wanderwine Prophets is six. You will need two blue mana and four colorless mana to bring Wanderwine Prophets from your hand and onto the battlefield. For what Wanderwine Prophets can do, the converted mana cost is well worth it for the most part. When used with some other cards, you can definitely get a lot out of Wanderwine Prophets.
What does Wanderwine Prophets do in the first place?
When you bring Wanderwine Prophets onto the battlefield, you have to Champion a Merfolk. If you do not, you have to sacrifice Wanderwine Prophets. When you Champion a Merfolk, you pick a merfolk creature and Exile it from the game as long as Wanderwine Prophets remains on the battlefield. You can pick a wimpy 1/1 merfolk creature to temporarily Exile from the game.
Wanderwine Prophets has only one special ability. This ability is pretty great for the most part. As a result, any blue control deck should have Wanderwine Prophets. If you attack with Wanderwine Prophets and manage to deal combat damage, you can sacrifice a merfolk. If you do, you get to take an extra turn. In this respect, Wanderwine Prophets is pretty much a built-in "Time Warp."
Time Warp is a blue sorcery spell originally printed in "Tempest" as a rare and reprinted in "Magic 2010" as a mythic rare. Time Warp allows you to take an extra turn. In regards to Wanderwine Prophets, you get to take an extra turn and not have to pay mana for it. All you have to do is sacrifice a merfolk creature.
Taking an extra turn lets you get another upkeep step, a draw step, an untap step, a combat step, and a summoning step.
There are ways to get the most out of this ability. You will need these cards on the battlefield: "Merrow Reejerey," "Merrow Commerce," "Lullmage Mentor," and "Summon the School."
Lullmage Mentor allows you to put a 1/1 blue merfolk token onto the battlefield whenever you play a spell or ability that counters a spell. If you tap seven untapped merfolk creatures you control, you can counter a target spell. In this respect, it is a built-in "Counterspell" that spits out 1/1 blue merfolk tokens. That should give you a steady amount of merfolk tokens that can be sacrificed whenever Wanderwine Prophets attacks and deals combat damage.
Summon the School is a white sorcery that allows you to put two 1/1 blue merfolk wizard tokens onto the battlefield. You tap four untapped merfolk you control to return Summon the School from your graveyard to your hand. You can combine this with Merrow Commerce which allows you to untap all of your merfolk at the end of your turn. Using this combination allows you to constantly produce merfolk that can be used to sacrifice for Wanderwine Prophets.
Merrow Reejerey can also be used because it lets you tap and untap target permanents whenever you cast a merfolk spell. You can use this with "Stonybrook Schoolmaster." Every time that Stonybrook Schoolmaster is tapped, you get to put a 1/1 blue merfolk wizard token onto the battlefield.
With these cards on the battlefield, you have an infinite combo. You can attack with Wanderwine Prophets, sacrifice a merfolk, and take an extra turn. With these cards on the battlefield, you have a chance to be able to produce plenty of merfolk tokens which can be sacrificed to constantly use the ability of Wanderwine Prophets.
However, you have to ensure that Wanderwine Prophets can deal combat damage. One way would be enchanting it with the "Whispersilk Cloak." It would give Wanderwine Prophets Shroud. It would mean that Wanderwine Prophets cannot be the target of spells or abilities. On top of that, it makes Wanderwine Prophets unblockable. Also, you can use "Deepchannel Mentor" which makes all your blue creatures unblockable.
Overall, Wanderwine Prophets is a good card on its own provided you have a few merfolk to sacrifice. With the cards already mentioned above, you can make this into an infinite combo. As long as you are able to produce those merfolk tokens, you can keep on taking one turn after another with Wanderwine Prophets.