There are two robin nonames that are rumored to use the radioactive symbol to make them nonames. Their names aren't like normal nonames (___), but they appear to be completely nonames. They arrive, they speak in a weird language and poo everyone out quickly. They sometimes answer when someone ex. tell them to stop or starts cussing at them for pooing them out.
Someone with a radioactive symbol in their name has been seen alone a few times, but those people are most likely imposters.
Times seen in-game
No one has seen the Radioactive nonames for a while, suggesting they have quit playing FLAB3.
EDIT: It appears they have returned, but no longer use the radioactive symbol to be nonames. What they currently use is unknown.