Does anyone remember Beast Boy? No, not that green kid; the real Beast Boy!
By the "real" Beast Boy, I mean the 30th century one who was part of the original Heroes of Lallor. Everyone remembers Gas Girl, Life Lass, Evolvo Lad, and Duplicate Boy (well, okay-- not everyone), but nobody remembers Beast Boy.
Like the rest of Heroes of Lallor, Ilshu Nor got his powers from one those wacky nuclear accidents so common on backward planets like Lallor. He could transform himself into any animal -- and he didn't need any color correction. The HOLs, by the way, were all part of the experiment in fan interactivity that was the Legion: the characters were all ones that had been suggested by fans in the Legion's letter columns. Beast Boy, in case you were wondering, was the brainchild of one Thomas Raimondo of Brooklyn NY (who I believe is now a doctor in Rhode Island) in a letter that appears in Adventure #309.
The Heroes of Lallor were all as dumb as rocks (including Evolvo Lad, despite his intermittently giantic cranium), starting their careers as the dupes of (of all people) Jungle King's brother, who used them as tools of revenge against the Legion.
They continued to pop up every once in a while (like Legion ancillary characters do), but mostly after Beast Boy left their team (which is why he is so largely unremembered).
You see, long before Grant Morrison did it with Animal Man, Legion writer Edmond Hamilton realized that being able to become other animals might alienate you from humanity... so that's exactly what happened to Beast Boy.
When the Legionnaires learn that Beast Boy had become a brooding loner, leaving Lallor to live with the animals on Vorn, they go to see him because, well, the Legionnaires are nosy busybodies (oh, there's some business about animals developing intelligence on Vorn, but the Legion always finds some excuse to butt in when they want to). Beast Boy threatens the Legion to get them to leave him alone, but when they refuse, he allows himself to be caught in animal form by a trapper collecting specimens for the Metropolis Zoo.
Later, Beast Boy escapes from the zoo by changing into a dog, in which form he befriends a little girl and he sacrifices himself defending her from a beast that he himself accidently released from the zoo during his own escape. Despite his emotional difficulties straddling the human-animal divide, he died appropriately enough as a dog, the creature that straddles both worlds most successfully, and the Legionnaires honored his heroism.
Legion story were goofy, yes. But the Legion brought a level of fan interactivity and psychological sophistication that hadn't been seen in DC comics books before, and we shouldn't let the "Plantetary Chance Machines" and "Traquiliz-Globes" obscure that for us.
So.... remember the original Beast Boy.