Aside: "Quick" can mean "alive" - I think that was its original meaning. We should also note that schnell is often translated as "quick" but I think "faster" is better in general. Using a simple dictionary approach to translate mordsschnell into English might come unstuck pretty quickly. With these clues we could arrive at living dead or zombie! I don't know but given how fast the above comment got downvoted that word has some history.