The Problem The Lazarus Monster. Bad CGI aside, its just a bit too big a leap from Lazaruss human form (Mark Gatiss). Admittedly its meant to be a genetic abomination that evolution aborted millions of years ago but its still hard to take seriously. Especially in the moments where its entirely intelligent and articulate despite being an enormous crab monster that reduces people to dried out husks. It also contrasts far too much with the episodes more philosophical moments when Lazarus is in human form and he and the Doctor debate the nature of mortality, complete with T.S. Eliot quotes. How To Fix It Redesign the monster to be something closer to a human but still some kind of genetic monstrosity. And rather than a CGI creature, have the monster played Gatiss in prosthetics. It would still be possible to have all the action sequences but with the added bonus of the monsters dialogue coming across better because it would be spoken by a real actor rather than dubbed over. Also, a prosthetic monster would blend much better with the sets and other characters in the episode than a CGI one. Especially since the episode already contains an excellent old age prosthetic for the 70 year-old Lazarus.