{T}: Add {C}. {3}{B}{G}: Until end of turn, this land becomes a black and green Plant Zombie creature with "This creature's power and toughness are each equal to the number of creature cards in your graveyard." It's still a land.
2005-10-01
While animated, Svogthos's power and toughness changes each time a creature card enters or leaves its controller's graveyard.
2008-08-01
A noncreature permanent that turns into a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn't matter how long the permanent has been a creature.
2009-10-01
Activating the ability that turns it into a creature while it's already a creature will override any effects that set its power and/or toughness to a specific number. However, any effect that raises or lowers power and/or toughness (such as the effect created by Giant Growth, Glorious Anthem, or a +1/+1 counter) will continue to apply.