Sleazy South African troublemakers Die Antwoord bring their circus of bad taste and big beats back on fourth outing Mount Ninji and Da Nice Time Kid. As ever, the alley-trash duo of Ninja and Yo-Landi Vi$$er keep it crass while rapping and angel-cooing over hip-hop beats and drug-fueled rave loops. A few contemporary updates mark an evolution (however small) this time around, including some dabbling with trap music on the charming "Fat Faded Fuck Face" and the Gucci Mane-sampling "Stoopid Rich." Production is the most polished it's ever been, thanks to the talents of G.O.D. (formerly known as DJ Hi-Tek, the oft-unseen third member of the group) and the Black Goat. Mount Ninji is front-loaded with some of Die Antwoord's best songs to date. The catchiest include the erotic "Gucci Coochie," a deeply seductive throbber that features Dita Von Teese; "We Have Candy," a deranged fever dream that includes a choir, a chest-punching beat, and a dizzying interchange between Yo-Landi and Ninja; "Daddy," which showcases Yo-Landi's full range and sounds a lot like fellow genre-blurrer Grimes, and "Banana Brain," a classic Die Antwoord raver that rides the sampled wave of Dark Oscillators' frantic "Stereophobia." Guest appearances add some distraction from the Ninja/Yo-Landi show, some hitting the mark better than others. Cypress Hill's Sen Dog brings the heat on "Shit Just Got Real," which samples Panom Promma's '70s Thai throwback "Mainaa Tam Pom Loey." Elsewhere, Jack Black dons his Tenacious D hat for "Rats Rule," a kooky carnival tune that sounds like an early Eminem song put through a meat grinder with some psychedelics, a sub-woofer, and one of Rob Zombie's dreadlocks. Young rapper Lil' Tommy Terror has the honor of showcasing his developing rap skills on a pair of lunatic tracks that will make or break the flow of the album, depending on the listener. Take the titles -- "Wings on My Penis" and "U Like Boobies?" -- and be the judge. The latter includes some problematic usage of the n-word by a team of white musicians, which, whether tongue-in-cheek or not, is still in poor taste. Another sophomoric interlude, "Jonah Hill," may be the first and only time the actor is compared to Ninja's testicles. Despite the distraction of these throwaway "skits" in the midsection, the album ends strong, with some of Die Antwoord's only (seemingly) genuine and vulnerable moments. Yo-Landi opens up on "Alien" and "Darkling," while Ninja reveals a surprisingly pretty singing voice on "Street Light." If one can make it through the slog in the middle, the ending is rewarding for those looking for a little more from the bratty pair after sticking with them for four albums of pretty much the same schtick. On the album cover, the dystopian crust-punks -- Yo-Landi looking like Harley Quinn as a neon babydoll and Ninja as a vampire rocking appropriated ethnic garb -- are standing in a garbage dump. It's appropriate imagery: Mount Ninji is a hedonistic party in a trash heap.