More fake namery on Wiki sites: Venom's symbiote offspring. If you were to trust Wikipedia, you'd believe Venom's offspring included Scream, Lasher, Phage, Riot and Agony. A shout-out to Wikipedia user Crazy Penguin, who explains the truth very well (and so I'll quote and credit him, rather than paraphrasing him):
http://en.wikipedia.org/wiki/Talk:Sy...)#LF_symbiotes
"Scream was never a fan name for the yellow symbiote character. She had an action figure produced in the Spider-Man: Venom: Planet of the Symbiotes toy line from 1996. The slim green symbiote character also had an action figure produced named Lasher. Unlike Scream, Lasher's name has never been used in a Marvel publication, but it still exists on an official Marvel product and so could still be considered his "real" name.
The other three Life Foundation symbiotes did not have action figures. There was an action figure called Riot, but that was a four-armed character who had never appeared in the comics and had a biography on the back of the box that made it clear he was not one of the five Life Foundation symbiotes.
Phage is short for Xenophage, an alien from the Venom comic books that is not a symbiote - it eats symbiotes. The Xenophage action figure was called Phage. I have absolutely no idea why a certain fan chose to use this name in reference to one of the Life Foundation symbiotes, it's a completely separate and unrelated character.
The name Agony comes from nowhere. It was just made up.
Allow me to reiterate, the only two Life Foundation symbiotes officially named were Scream (the yellow one) and Lasher (the green one), both in the action figure line. The only one to have their name carried over into the comic books and publications is Scream.
Officially the others do not have codenames until Marvel tells us otherwise."
Unfortunately Crazy Penguin appears to be outnumbered by the misinformed, as a glance at the history of the various symbiote pages (most of whom are listed under the fake, fan-cruft names) shows that whenever he (or anyone else) has tried to fix the pages, others have rushed to return them to being incorrect.
So, summarising. Scream is an official name. Lasher is not an official name, but, in the absence of an official name, does have some legitimacy for being used to clarify which symbiote is being discussed, based on it being used by the toy line. Riot, Phage and Agony are just plain wrong.