Guys a little culture info in hinduism, there is actually a god who has a third eye, he is 'Shiv'. He is the god of many things mostly death. But people pray to him with love. So in a way, a lovable version of Hades. In India, lord shiv comes to mind whenever any mention of third eye is talked about. And when that opens, bad things could happen. It is also associated with him seeing everything.
This sentence uses “forehead” which is a part of the “face”, not “head.” My eyes are part of my head, but they are not completely in my head. Much of my eyes are visible on my face. Be careful with the word “never”, and define the word “we” whenever you can. Yes, “eyes in the back of his head” is an established expression. Now, think about “forehead” which is already not in your head, but on the front of it.
Is this idiomatic? I was thinking it might be comparable to a saying in English like "he has eyes in the back of his head."
This is an irregular plural. We might understand how the plural of one hair “cheveu” can become “des cheveux” and a coat “un manteau” can become “des manteaux”, but in French nouns ending in ‘l’ can get a plural ending with an ‘x’ also, “un cheval” becomes “des chevaux” and “un travail” becomes “des travaux”.
There is a y sound in the pronunciation of œil, so although the shape of the words are very different, I could see how with time the vowel sound might have disappeared from the beginning of the plural.
So how would you say, "It has a third eye on the forehead"? I suppose the translation is, "Il a un troisième œil sur le front." How are we to know whether you intend "he" or "it"? In NZ, there is a reptile with a third eye on the forehead, at least, a light-sensing organ.