Answer by taking a quote from the following article:

Guttermouth is an American punk rock band formed in 1988 in Huntington Beach, California and currently recording for Rude Records/Bird Attack Records. They have released nine full-length studio albums and two live albums and have toured extensively, including performances on the Vans Warped Tour. They are infamous for their outrageous lyrics and behavior which are deliberately explicit, offensive and intended to shock, though usually in a humorous and sarcastic manner. This behavior has sometimes resulted in high-profile problems for the band, such as being banned from performing in Canada for eighteen months and leaving the 2004 Warped Tour amidst controversy over their political views and attitudes towards other performers.

The following year found the band returning home to California and experiencing a lineup change. Clint Weinrich married in the spring of 1995, and to fill in for him on a European tour the band recruited Steve "Stever" Rapp, a college friend of Nunn's who was playing in a band called The Grabbers. Things worked out well with Rapp on this tour and he soon became the band's permanent bass player. The new lineup entered the studio and recorded their third album Teri Yakimoto. By all accounts the recording process was plagued with problems, and at one point most of the recordings were scrapped and re-recorded with a new producer. The result was an album that continued the fast and sarcastic Guttermouth tradition but was more melodic and pop-influenced than their previous albums. The band continued to tour and expand their fan base, and filmed a music video for the song "Whiskey." With their popularity growing Nitro Records re-released Full Length in CD format with bonus tracks under the title The Album Formerly Known as Full Length LP.  In 1997 the band recorded Musical Monkey, an album which captured their chaotic energy and sharp sense of humor. It is considered by many to be the best representation of their "classic" sound, and songs such as "Lucky the Donkey," "Do the Hustle," "Lipstick" and "Perfect World" became staples in their live set. The following year they released Live From the Pharmacy, a recording of a live show from 1994 that also included four new songs engineered by Vandals guitarist Warren Fitzgerald and liner notes written by Nunn recounting the band's history. In 1998 Guttermouth was banned from performing in Canada for one year on charges of public indecency after Adkins exposed himself onstage in Saskatoon. According to Adkins: "oh, I was guilty [...] What I would do is grab two young girls out of the audience and I would have them hold up this sheet in front of me, and Jamie, the drummer at the time, would say this magical incantation, if you will, and I would be standing there stark naked." Combined with a drunk driving charge from the United States, the incident led Adkins to be arrested on immigration charges, detained for five days, and then deported, though Guttermouth would return to Canada a few years later. After obtaining a full pardon from the Canadian judicial system known as the crown. No record remains on file.  Rapp left the band in 1999, at which point Nunn moved from drums to bass and new drummer William "Ty" Smith was brought in. That year the band recorded and released Gorgeous, their most aggressive album to date and their final album for Nitro.

Who replaced Rapp after he left the band?
Nunn moved from drums to bass and new drummer William "Ty" Smith was brought in.