Dragonskull Summit

Type: Land
Set: Archenemy: Nicol Bolas #93 (rare)
Price: $0.88 USD

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Dragonskull Summit has 31 printings, first in Magic 2010 (2009). EDHREC ranks it #82 among Commander cards. It appears most in Sauron, the Dark Lord decks (27,312 on EDHREC). 14 public decks on TCG run it. It has 2 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: legal
standard: not legal
brawl: legal

Public decks that run Dragonskull Summit

Blight Curse - Lorwyn Eclipsed Commander Deck, led by Auntie Ool, Cursewretch
Break the Chains, led by Caesar, Legion's Emperor
Doom Prevails - Marvel Super Heroes, led by Doctor Doom, King of Latveria
Endless Punishment - Duskmourn: House of Horror Commander, led by Valgavoth, Harrower of Souls
Hail, Caesar - Fallout, led by Caesar, Legion's Emperor
Hosts of Mordor - Tales of Middle-earth Commander, led by Sauron, Lord of the Rings
Klingon Fury - Star Trek Commander, led by Worf, Defiant Commander
Legends' Legacy - Dominaria United, led by Dihada, Binder of Wills
Mardu Surge - Tarkir: Dragonstorm Commander, led by Zurgo Stormrender
Masters of Evil - Doctor Who, led by Davros, Dalek Creator
Most Wanted - Outlaws of Thunder Junction Commander, led by Olivia, Opulent Outlaw
Open Hostility - Commander 2016, led by Saskia the Unyielding
Revival Trance - Final Fantasy Commander, led by Terra, Herald of Hope
Turtle Power! - Teenage Mutant Ninja Turtles Commander Deck, led by Heroes in a Half Shell

Commanders that run Dragonskull Summit most

Deck counts from EDHREC.

Sauron, the Dark Lord: 27,312 decks
Valgavoth, Harrower of Souls: 25,296 decks
Edgar Markov: 22,035 decks
Kaalia of the Vast: 19,516 decks
Auntie Ool, Cursewretch: 17,521 decks
Fire Lord Azula: 17,333 decks
Kuja, Genome Sorcerer // Trance Kuja, Fate Defied: 17,095 decks
Caesar, Legion's Emperor: 16,946 decks

Often played with Dragonskull Summit

Cards that show up in the same decks on EDHREC.

Rulings

2009-10-01: As this is entering, it checks for lands that are already on the battlefield. It won't see lands that are entering at the same time (due to Warp World, for example).
2009-10-01: This checks for lands you control with the land type Swamp or Mountain, not for lands named Swamp or Mountain. The lands it checks for don't have to be basic lands. For example, if you control Stomping Ground (a nonbasic land with the land types Mountain and Forest), Dragonskull Summit will enter untapped.