This card's art and concept is a reference to
many different things where an entire swamp or
other region of land stood up and started coming
after people. But personally, I think of
shambling mounds from Dungeons and Dragons, and
specifically the Forgotten Realms conflict
between Thay and Aglarond, where the Red Wizards
animated large numbers of shambling mounds and
people who drowned in the swamp and sent them
walking in the general direction of Aglarond.
That ended about as well as you might expect.
Diregraf Colossus, for its part, takes black's
theme of parasitism in an intriguing direction.
It's clearly at its best when all or almost all
the spells in your deck are zombies, but that
means you will have fewer of black's other
signature effects. There are few creature decks
that aren't helped by things like Sign in Blood
or Ultimate Price. I suspect, though, that that
way of looking at it may actually be too
dichotomous: even in a deck with a more "normal"
ratio of creatures to non-creatures, the
Colossus will often enter as a 4/4 or higher,
and even one extra zombie token can give you the
edge in a battle of attrition.
This begs the question, would a gravecrawler
reprint have been too much to ask for?
Seriously, for a horror themed block, it seems
like there are very few good zombies in this
set. I like this one though.