Cheapest priced copy (Commander Masters): $0.79 at Card Kingdom, near mint, their price list as of .
Lorthos, the Tidemaker 
Legendary Creature — Octopus · 8/8 · Mythic · Zendikar · #53
Whenever Lorthos attacks, you may pay {8}. If you do, tap up to eight target permanents. Those permanents don't untap during their controllers' next untap steps.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
6 printings · $0.79 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2014 | 117 | Mythic | $0.99 | — |
| Commander Masters | 103 | Rare | $0.79 | $1.49 |
| Commander Masters | 490 | Rare | — | — |
| Marvel Universe (Doc Ock, Armed and Dangerous) | 10 | Mythic | $0.99 | $1.49 |
| The List | ZEN-53 | Mythic | $0.99 | — |
| Zendikar | 53 | Mythic | $0.99 | $3.99 |
3 rulings from Wizards of the Coast
- 1 October 2009If a targeted permanent is untapped at the time its controller's next untap step begins, this ability has no effect on it. It won't apply at some later time when the targeted permanent is tapped.
- 1 October 2009If an affected permanent changes controllers before its old controller's next untap step, this ability will prevent it from being untapped during its new controller's next untap step.
- 1 October 2009You may target any eight (or fewer) permanents. It's okay if any of them are already tapped, and it's okay if any of them are controlled by someone other than the defending player.