Mad Gardener (Our Strange and Wonderful House)
The Conservatory of the Strange and Wonderful House, really a version of the Garden of Eden, was guarded by a Mad Gardener who was really an angel.
Although his true form was a many-winged angel wielding a flaming sword, he could make himself be perceived as a wizened old man with a machete, though mirrors would reveal his true nature. He had “a deep but strangely serene voice”. (PROSE: Our Strange and Wonderful House: View From a Jungle, Back to the Garden)
After entering the Conservatory, one visitor to the house bumped into the Mad Gardener, who began chasing after them with a machete, singing a nonsense-song all the while. (PROSE: Our Strange and Wonderful House: Back to the Garden)
Behind the scenes
This Mad Gardener's song is in fact The Mad Gardener's Song by Lewis Carroll, quoted from Sylvie and Bruno, although they are otherwise distinct.