It is a multi-genre concept album with a dark nautical theme, with most songs incorporating elements from psychedelia and/or sea shanties, while also featuring a heavy progressive rock influence.

Starting with the release of their 1994 album Chocolate and Cheese, Aaron Freeman and Mickey Melchiondo—known by their stage names Gene and Dean Ween, respectively—began to significantly enhance their approach to studio recording.

It also notably began their transition from a duo to a more traditional band with the addition of drummer Claude Coleman, allowing Freeman and Melchiondo to experiment with a wider range of musical styles than they could with the drum machine they had used on previous releases.

After recording 12 Golden Country Greats in 1995 and releasing and touring behind it, Ween completed the remaining tracking of The Mollusk at various inland locations.

[6] AllMusic describe it as being another "multi-genre extravaganza" like Chocolate and Cheese, in contrast to 12 Golden Country Greats, which focused on a single genre.

[20] Kurt Vile named "Mutilated Lips" his favorite song of all time, and recalled that the album "blew [his] mind" when he listened to it as a teenager.