The ominous, deep cleft high and left on Thatchtop, above the Loch. Usually best approached from the right after climbing Necrophelia (though other ways, including a sometimes formed direct chimney, can be had), making for a great day of hard ice and mixed. From the shelf atop Necro, the climbing is easy and rambling to reach the crux final pillar, which is most often climbed as a steep ice pitch. However, when the pillar isn't touching, there can be brilliant mixed climbing - fairly hard, and all free-hangers are serious (and pumpy!), of course. These conditions are normally found early season, so be ready! A great route.
If it's all ice, it can protect with all ice screws. However, excellent cracks border the bottom half of the left-hand side of the crux final pillar - assorted nuts, and finger to hand-sized cams to form a medium rock rack are good. There's a fixed anchor at the top and in the gully all the way down (unless you walk-off left), but be prepared to leave your own if you can't find them or they're gone.