Hildegard Gardener
Although it's not necessarily clear how many of the residents of Teras Terrace got their names, Hildegard Gardener chose her surname herself. She may have chosen it in part because she likes the fact that its first syllable is the same as the last syllable of her first name ("Or you can call me 'Hildegardener'!", she sometimes says), but it's an occupational name, as Hildegard considers herself something of a gardener, though what she "gardens" isn't plants but some kind of substance resembling (but definitely not) coral that grows all of her home. She often employs some of the local youth to help her keep it trimmed away... after all, she says, you know what would happen if it got out of hand! (The Mongleys, at least, do not know what would happen if it got out of hand.) While Hildegard may not have intentionally planted her "garden", she does get some benefit from it, as she grates the trimmed pieces of the growths and sells them to markets outside the Terrace as protein powder.
Hildegard has no defined top or bottom, and often switches which end she considers up just because she feels like it.