Skeleton Key
Artifact — Equipment
Equipped creature has skulk. (It can't be blocked by creatures with greater power.)
Whenever equipped creature deals combat damage to a player, you may draw a card. If you do, discard a card.
Equip 
Commander bracket
Derived from card traits, not a ruling — bracket rules turn on how a deck intends to use a card. Bracket rules
EDHREC
Combos
Not part of any combo on Commander Spellbook.
Format legality
Rulings
- 2016-04-08
If you cause a creature to have 0 power or less, use the actual value (which may be negative) to determine whether it can block or be blocked. A creature with skulk and 0 or less power most likely won’t be blocked, but it won’t deal combat damage and won’t trigger any abilities that trigger when combat damage is dealt.
- 2016-04-08
Skulk matters only as blockers are chosen. Modifying either creature’s power after blockers are chosen won’t cause the attacking creature to become unblocked.