The 6 legged reptilian scientists were the Chamachies, and their special ability is Instant Discovery, ie, any tech they were researching currently, could be completely finished, regardless of time left. Great for those really long technologies.
Being a Research lover myself (love tech rushes and such), the Chamachies were my favorite race, although I also liked playing the Hanshaks, who could communicate with all the aliens from the beginning, and the Balifids, who were awesome diplomats who could force peace treaties.
As for the race you hated playing against, they were the Dubtaks, who could steal all technology if owned by at least 2 races. And it really is all. A single use of their special ability could allow for an instant discovery of a dozen technologies. Theoretically, if you played the Dubtaks, and isolated yourself, ignoring your own tech until 2 other races finished everything, you could instantly have every technology, then you could freshly expand on every world without having to destroy structures to build more efficient ones, or removing tubes so you can terraform the black squares. I've done something similar to that, just teching up with a couple planets and no ships, waiting, then using the ability to get many nice techs.