FOILCheapest priced copy (Hour of Devastation): $0.49 at Card Kingdom, near mint, their price list as of .
Kefnet's Last Word 
Sorcery · Rare · Hour of Devastation Promos · #39s
Gain control of target artifact, creature, or enchantment. Lands you control don't untap during your next untap step.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.49 to $1.29 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Hour of Devastation | 39 | Rare | $0.49 | $0.49 |
| Hour of Devastation Promos | 39s | Rare | — | $1.29 |
6 rulings from Wizards of the Coast
- 14 July 2017If the target permanent is an illegal target by the time Kefnet’s Last Word resolves, the entire spell doesn’t resolve. Your lands will untap during your next untap step as normal.
- 14 July 2017No lands that you control will untap during your next untap step, even lands that aren’t tapped as this spell resolves. This includes lands that enter the battlefield after this spell resolves.
- 14 July 2017In a multiplayer game, if a player leaves the game, all cards that player owns leave as well, and any effects that give the player control of permanents immediately end.
- 14 July 2017The control-change effect of Kefnet’s Last Word lasts indefinitely. It doesn’t wear off during the cleanup step.
- 14 July 2017If more than one spell says that lands you control don’t untap during your next untap step, the effects will all wear off during that untap step. You’ll untap lands you control during your untap step after that one.
- 14 July 2017Gaining control of a creature doesn’t cause you to gain control of any Auras or Equipment attached to it. They’ll remain attached, but an Aura’s effect that affects “you” still affects its controller rather than you, the controller of an Equipment can move it during their next main phase, and so on.