It wasn't anything overly spectacular as such.
I just personally liked having a basic story, aim or personality behind the mobs I designed with Glyph.
Gillyweed was doing to be inspired by the Gillyweed obviously from Harry Potter, but twisted in with the rest of that challenge. We were hoping to make it force the player water property, web the player as a strangle, blind the player (it's getting dark nowww), then effectively "drown" you to death.
It was a sadistic, feeding little plant by the end, but we had trouble making the player convert work, let alone a way we were happy with.