Dragonskull Summit

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

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.