The two headed giant shows up in MtG online articles, either as an aside when talking about the 2HG format or when talking about terrible puns (Foriys is pronounced "four eyes"). Recently joined players who don't read online and didn't happen to face that Avatar in its Eighth Edition reprint (I for one didn't) are frankly unlikely to recognize
either card.
In Nacho's position, I personally would have referred to
Anurid Swarmsnapper, which has an ability that is exactly like what Nacho mistakenly thought I was saying Feywarden presently has. But that card is even less memorable.