I don't know how it got in but it's living in the cupboard under the stairs. I went to fetch the magic mop and there it was, glowering at me and muttering. I caught the words "vile" and "grim" but the rest of it was incoherent because it kept spitting between the words.
I've ordered some manic pixies as I've heard they can be effective in getting rid of trolls. The pixies will arrive tomorrow (thank god for Amazon Prime!) but in the meantime, does anyone have any other ideas of how to deal with it?