Sometimes considered a subfeature of the Mount Washington shield volcano, Hoodoo forms one of several glaciated remnants of Pleistocene volcanoes in the region, other nearby examples including Maxwell Butte and Cache Mountain. It is a cinder cone and possesses an intact summit crater, since the neighboring andesite lava dome of Hayrick Butte prevented Pleistocene glaciers from reaching Hoodoo's summit.
Hoodoo can be seen as part of the Mount Washington shield volcano; it forms one of several glaciated remnants of Pleistocene volcanoes in the area. Other nearby examples include Maxwell Butte and Cache Mountain. It is a cinder cone with an unaltered summit crater, due to the neighboring andesite lava dome of Hayrick Butte preventing Pleistocene glaciers from reaching Hoodoo's peak.