Simplify the following text for a Grade 8 native English-speaking person.
Original: Krist Anthony Novoselic II ( born May 16 , 1965 ) is an Croatian-American rock musician , best known for being the bassist and co-founder of the grunge band Nirvana .
Simplified: Krist Novoselic , born Krist Anthony Novoselic II , is an American rock musician . He is most famous for being the bass player for the popular grunge band Nirvana with Kurt Cobain and Dave Grohl .