The Mad Mudarch has two attacks that have been accidentally both named Royal Flush, when one should be Bog Bequest. This is presumably because of a misreading of the Japanese names, ドロドロ外無双 and ドロドロ内無双, which are different by one kanji.
ドロドロ外無双 has previously been localised as Bog Bequest, while ドロドロ内無双 is correctly localised as Royal Flush.
This mishap leads to the boss having no tell for close and far attacks.