In Menachos 37a, there is a part which involves someone named "Plimo" (פלימו):
בעא מיניה פלימו מרבי מי שיש לו שני ראשים באיזה מהן מניח תפילין א''ל או קום גלי או קבל עלך שמתא
Plimo asked Rabbi: If someone has two heads, on which one does he place the tefillin? He said to him: Either leave, or regard yourself under a ban.
Plimo also appears in Kiddushin 81a through 81b, in another quite humorous story involving him and the Satan, and there he is called a Tanna. He most likely appears elsewhere in the Gemara too, but I don't know where else off-hand.
."אצל חז"ל מוזכר לעתים תנא בשם "פלימו" – ויש שהסבירו שאין זה שם אדם מסוים, אלא כינוי כדוגמת "פלוני
In Chazal, a tanna is sometimes mentioned as "Plimo" - and some have explained that this is not the name of a certain person, rather it is a nickname such as "Ploni".
(For those who are not familiar with the term "ploni", it is the Hebrew equivalent to "John Doe".)
Who is Plimo? There certainly must be some who consider him to be a Ploni, but is there anyone who tries to identify him, perhaps similar to יש''ו where some say it is an acronym and others say the acronym is also a name (Yeshu) and refers to you know who?