Okilly Dokilly is a hardcore metal band — um, make that “Nedal” band — from Phoenix that performs music inspired by Ned Flanders, the Bible-thumping, Homer-loving character from “The Simpsons.” To drive the point home, all the members of the band also dress like Flanders, with a signature green V-neck sweater, round frame glasses and mustache. The group performs at Slim’s on Friday, April 28, with Beatallica, a band that performs Beatles songs in the style of Metallica.