Whenever Karn blocks or becomes blocked, it gets -4/+4 until end of turn.
: Target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value until end of turn.
If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.
Create a token that's a copy of target creature.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)
: Target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value until end of turn.
: Target permanent becomes an artifact in addition to its other types until end of turn.