This seems to me to be the kind of move that is vague on purpose, with the expectation that it will vary from campaign to campaign. Dungeon World has a lot of this sort of thing. The short answer is: figure out what makes sense in your story, and go with that.
Personally, I would be inclined to handle it as particular kind of Ritual, and require that it takes months of preparation and construction and thousands of coin in materials to build the tower/cave/ritualarium, require a quest to retrieve a vial of Pure Chaos, and then a solid three days of active ritual. But then, that might not jive with how magic works in your game.
Anybody have stories of a wizard in their game who actually did this?