Tantalus (Ancient Greek Τάνταλος) son of Thyestes was an infant named after his infamous ancestor of Sipylus. In Hyginus' account of the Atreid feud, Atreus murdered him (with Pleisthenes) and served the children to their father Thyestes at the revenge banquet — a horror that curses the house of Pelops.
Adapted from Wikipedia, "Tantalus (son of Thyestes)" · CC BY-SA 4.0
I.The banquet of Atreus
Hyginus makes Tantalus and Pleisthenes sons of Thyestes by Aerope, wife of Atreus. In revenge for adultery and betrayal, Atreus kills the boys and feeds them to Thyestes — the Thyestean feast that becomes a byword for familial atrocity.
The atlas keeps this banquet victim (tantalus-infant) distinct from Tantalus of Sipylus (tantalus) and from Tantalus the Younger, Clytemnestra's first husband slain by Agamemnon (tantalus-clytemnestra-husband). Wikipedia's article on "Tantalus (son of Thyestes)" conflates the banquet child with the adult first husband; the atlas separates those strands.
II.Homonyms
Three Pelopid Tantaluses: the Sipylean sinner; the Thyestean banquet infant; and Clytemnestra's first husband. Same name, three nodes.