To find this climb, locate the far south end of The Gym (where it meets the east corner of Spiney Ridge). Arrowhead Spire is the small detached pillar. Just to the north of this is a tall triangle shaped wall. On the right side of the wall is a slabby arete with dark grey rock with bolts. This is Black Mamba Arete.
Cruise up the corner on edges and flakes. The rock quality isn't that great, but it makes a good quick warmup (or something to run up while you are waiting for the rock to warm up). There isn't any particular crux to speak of. Be careful for loose rock.
Runout between 2nd & 3rd bolts might not have been the best idea. Easy climbing, yes, but crappy rock there, and if something blows, there is groundfall potential. Fun moves on better rock up high, but it seemed a little thin compared to other 8s at Shelf.