Though anime dubs have taken strides over the years, some past examples are simply laughably terrible in all respects. Some contain bad acting, awkward translation and clumsy pronunciation of Japanese names -- as if the actors choked on the foreign words, for some reason, as they tumbled from their resisting lips.
It is important to distinguish that some dubs, like the dub for Ghost Stories, are goofy and silly by design. Therefore, gag dubs do not count for this list. This is a list exclusively for the anime dubs that either lacked coherency or proper clarity when watched, proving at best unintelligible and at worst the best-worst thing you'll ever see... and hear.
Honorable Mention: Cyber City Oedo 808
The dub for Cyber City Oedo is fairly on-par for the sort of dub one would see in the early '90s. For this reason, it's hard to distinguish it as particularly bad. However, there is a single line in the dub that has become so incredibly infamous that it requires an honorable mention before we get to the list proper.
The anime maintains an edginess throughout, which is reflected in its vulgarity-laden dub. However, one line is so infamous it has become synonymous with this era of anime dubbing.
Devilman (OVA)
Fans of Devilman: Crybaby might have forgotten that there were multiple adaptations of Go Nagai's manga before the most recent Netflix anime. One of them was Devilman, an OVA from the early '90s that was, for many international audiences, their first introduction to the series. While it remains a cult classic, its dub is admittedly terrible. The acting is flat and wooden and the writing is notoriously awkward and artificial sounding. Nihilistic and vulgar remarks are delivered with either a childlike glee or edgelord intensity, which just makes the whole thing absurd.
However, for many, that just adds to the charm. Sure, the cheesy acting siphons any potential horror away in any given scene, but that is part of what makes this OVA so memorable for so many fans. Devilman is a classic, and its dub remains one of the best-worst anime dubs of its era.
Dragon Ball Z (AB Groupe Dub)
Ever hear of the "Big Green" dub of Dragon Ball Z? While Ocean Group and Funimation were dubbing Dragon Ball Z, another dub produced in Europe by the French dubbing company AB Groupe localized the series for a very different audience. Specifically, AB Groupe dubbed the films and specials for Canadian and British audiences. YTV chose to not broadcast any of them because the dubs by AB Groupe are bad. So, so bad.
On top of none of the voices fitting the characters and the clumsily written script, the dub seems to avoid using specific terms that are now forever associated with the series. The AB Groupe seemed embarrassed to call Saiyans, Scouters, or ki blasts by their canonical names, instead opting for "space warriors," "portable computers," and "fireballs." But the worst thing? When Piccolo shows up, Gohan shouts "Hey! It's Big Green!" That's why, as this line has become so infamous that the AB Groupe dub, it is now forever known as the "Big Green Dub."
Garzey's Wing
Garzey's Wing is an infamously terrible isekai from the mid-'90s. And among English-speaking fans, possibly the worst part of all is its poorly mixed English dub that fails to coherently relay the already poorly written anime in front of you. Of course, there are several incompetent dubs from this era, but the problem with Garzey's Wing is not simply that it is badly acted and badly written.
It's also shrill and agonizing to the ears. This is a dub that actually hurts you if you listen to it for too long. That, in many ways, makes it worse than just about any other sort of bad dub.
Nausicaa of the Valley of the Wind (Warriors of the Wind Dub)
Never heard of Warriors of the Wind? That's probably because you know it better as Nausicaa of the Valley of the Wind. Long before the modern dub of this Miyazaki classic, Manson International released a super truncated version of Nausicaa. However, in order to make the film "better suited" for a western audience, Manson International made drastic changes to the source material. The changed title is just the tip of the iceberg.
The film featured poor acting and a bizarrely rewritten script. However, it is most famous for omitting a half-hour of the original anime classic. Much of the removed content consisted of slower scenes that developed the characters and the world. This resulted in a soulless adventure film where events happened largely without context. Miyazaki notoriously hated this dub so greatly that he ensured it never was released after the mid-'90s; instead, it was replaced in circulation by the Walt Disney dub that fans can now enjoy. This is a dub so terrible you can't even find it on modern home media.
One Piece (4Kids Dub)
4Kids might be one of the most infamous dubbing companies around, and its One Piece dub might be one of the most infamous dubs of all time. Yes, the 4Kids dub has bad acting, but that bad acting is a symptom of the awfulness rather than its cause: 4Kids wanted to turn One Piece, a show for older teens, into something for four-year-olds.
While all translators employed localization in order to adapt it for a different audience, 4Kids, under the mask of "localization," drastically altered the plot and animation of One Piece. The entire script is rewritten to turn this often dark series into something young kids could watch. Even ignoring the massive animation alterations -- turning guns into water pistols, turning cigarettes into lollipops, removing all explicit violence, and so on -- the dialogue is twisted into something garishly and artificially kid-friendly.
Some 4Kids dubs, like for Yu-Gi-Oh! or Pokemon, still work despite their obvious flaws because the dubs do not destroy the plot and characters. Sometimes, the censoring even becomes entertaining in some way -- like Yu-Gi-Oh!'s "finger guns" or Pokemon's "jelly donuts." One Piece is different. In the process of softening its edges, 4Kids maimed One Piece's characters, thus ruining any of its compelling drama.