The Oankali are an intriguing alien race of natural genetic engineers in
Octavia Butler's excellent
Xenogenesis trilogy. There are three
sexes:
male,
female, and the
seductive ooloi. The four-armed ooloi are able to manipulate genes directly, and after merging with humans, are able to shape shift, an ability gleaned from studying
cancer in humans. The oankali are peaceful
vegetarians.
They all have names that sound neat.
Nikanj. Tehkorahs. Kahguyaht. Ahajas. Dichaan. Dehkiaht. Jdayeh.