The Tenth Annual ICFP Programming Contest was a 72-hour contest held July 20?23 2007 and organised in conjunction with the 12th ACM SIGPLAN International Conference on Functional Programming (ICFP 2007). As in the previous nine editions, the goal of the contest was to allow teams from all over the world to demonstrate the superiority of their favourite programming language. This year's task was to reverse engineer the DNA of a stranded alien life form to enable it to survive on our planet. The alien's DNA had to be modified by means of a prefix that modified its meaning so that the alien's phenotype would approximate a given "ideal" outcome, increasing its probability of survival. In this report we describe the task, how to solve it, how we created it, and how the contestants fared. About 357 teams from 39 countries solved at least part of the contest. The language of choice for discriminating hackers turned out to be C++.