Like many other "Frog" monsters, this card's Japanese name is a pun: the kanji "鬼", normally read as "oni", can also be read as "ki", and this card reads "kigaeru", which also means "to change one's clothes".
This monster could possibly be the antithesis to "Treeborn Frog". While "Treeborn Frog" looks angelic with wings and a halo, "Swap Frog" has two horns that are usually depicted on demons. He also has a tight card combo with "Treeborn Frog". The word "Oni" can refer to many things: Ogre, Troll, Demon or Curse/Maledict.
The devil theme is also emphazise in its effect since it can send an Aqua-type monster to the grave when it's summoned.