This is a very old Magic deck that dominated Legacy for a long time. It was unstoppable. It was the Faeries/Jund/Affinity/Whatever of its day.
I certainly didn't come up with it, some Canadian guy did or something, but I thought I'd enter it into the competition here as an homage.
It is based on what is unquestionably the most lethal combo in all Magic-
Jackal Pup
/
Muzzle
/
Donate
/
Farrel's Mantle
/
Aysen Highway
/
Balduvian Shaman
/
Mossdog
/
Bloodshed Fever
/Chronatog//
Coalition Flag
/
Obelisk of Undoing
/
Great Wall
.
First, cast
Jackal Pup
. Enchant it with
Muzzle
and
Farrel's Mantle
and
Bloodshed Fever
and
Donate
it to your opponent. Next, get out a Plains and and
Aysen Highway
and a
Balduvian Shaman
to change white to red so you can't block the Jackal Pup. Then, cast
Mossdog
. Put
Coalition Flag
on the
Mossdog
so that your opponent has to target it with the ability of
Farrel's Mantle
. Next, to accelerate the process, since honeymomo did want this combo to go off soon, get out a Chronatog to skip a bunch of turns and accelerate your combo to super speed. Each turn your Mossdog will grow bigger because you can't block it due to
Aysen Highway
+
Balduvian Shaman
naming red, they have to attack because of the
Bloodshed Fever
+
Jackal Pup
, they don't hurt you because of
Muzzle
, and they have to target Mossdog with
Farrel's Mantle
's ability to make Mossdog bigger.
Eventually you will have like a 20/20 Mossdog. Now, when you're ready, use your
Obelisk of Undoing
to bounce
Muzzle
, and then play your ULTIMATE finisher-
Great Wall
. BOOM.
Jackal Pup
loses plainswalk, attacks in your 20/20 Mossdog, and your opponent DIES.
You can see how this deck just wrecked the format until Wizards banned the important cards. You don't even see any cards that have anything to do with plainswalk anymore because it is so incredibly broken.