Hey there,
A few months back I found a bugged interaction on stream with “Felhound Portals” and “Arch-Villain Rafaam”, where the “Felhound Portal” is flashed when drawn, even though it was changed into a random legendary. The clip for this can be found here.
Reproduction Steps:
My opponent played either “Portal Keeper” and/or “Portal Overfiend”, shuffling 3 “Felhound Portals” into their deck. A few turns later, they played “Arch-Villain Rafaam” turning their hand and deck into legendaries. The “Felhound Portal” was shown anyway when drawn.
I have not tested this with Bombs or the Mine from “Iron Juggernaut”, the Cursed Blood with “Hakkar”, Candles from the “Darkness”, spells generated by “Deck of Wonders”, Ancient Curse from “Ancient Shade”, or the Spiders from “Beneath the Grounds”/“Fal’dorei Strider”, but those may be the same.
Hope this helps!
-Scrabz