My answer is Professor Craig Venter and the cat is 'Synthia' the artificial bacterial life form he has developed. I believe that this finally destroyed any covenant we ever had with creation and is potentially the most devastating application of humankind's technological skill. Venter and his team claim that 'fail safe's' have been inbuilt to prevent this bacterium ever becoming a danger by removing DNA associated with such traits. The problem with this is that bacteria are nothing more than DNA and a few simple cell organelles and it's principal purpose is to reproduce it's DNA which it does very rapidly and each time it does the possibility for mutation arises. Venter claims with pride that this has already occur over a million times in 'Synthia's' case.
The 'Synthia' developers claim that it can only grow/reproduce in a particular Petri dish but the ubiquitous nature of DNA tells us that it's very purpose is to overcome limits to growth and as such it will sooner rather than not find a way to mutate to overcome any confines we apply to it.
Nature over 4 Billion years has found a way of marrying particular DNA constructs to balancing ecosystems which prevent the dominance of any given species but where mankind has interfered with this disaster has ensued in many cases, for example the introduction of Rabbits to Australia or the Grey Squirrel to the UK. This even occurs with plants, one only has to take the case of the Rhoddendron or Japanese Knotweed to see the disastrous consequences of our lack of understanding. In these cases it is fortunate that the organism are large enough and have a slow enough reproductive cycle to allow us to manage the impacts of their introduction. It should be noted however that to date in all cases eradication has proved impossible and at best it is a never ending damage limitation exercise.
This will not be so easy should 'Synthia' and her cousins get out of control and the likelihood is that sooner or later there will be massive pandemic or the emergence of drug resistant strains of existing bacterial infections. The rapid rate of reproduction and mutation associated with bacteria will make a managed response impossible.
As ever the technological hubris embedded in this kind of development beggars belief, somehow the likes of Venter need to be put firmly back in Pandora's box, if we are to avoid self-inflicted suffering on an unimaginable scale.