Not exactly a rare sight for Ace, but not a common one either.

Or If on anyone else's account, most likely the first and last time they see this.

The inside of the maw is covered in a lipid like fat, similar to the feels of frog tongues or fish. It's hydrophobic and attaches to any nearby solid object in this case the food and makes it nearly impossible for one to hang-on, for even in the water given it's nature, will feel as slipper as ice. This mucus of sorts is all purpose for easily swallowing prey whole without much struggle.