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, and later a demon.
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) Still chased by the Gardener, the visitor took a wrong turn and, running out of path, ended up reluctantly running out of the marked path and into the foliage. There, they soon reached a dead end, their way cut off by a wall of glass panels which soon reflected a vision of horror: the Mad Gardener's true angelic form morphing into a demonic one. The Gardener managed to plant the machete in the chest of the visitor's body armour, though it held and they were not injured. Keeping them on the ground, the Gardener yanked out the machete and prepared to behead the visitor. (PROSE: Our Strange and Wonderful House: The Madman)
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.