Principally: The Knack.
I recently learned that the Knack were accused, back in their day, of ripping off the Beatles, not just in their sound / music, but also in their packaging / marketing. A backlash followed the release of their blockbuster debut album, "Get the Knack", and the perception that the band had stolen full-out from the Beatles, and the accusation, hung over the band. The band, and their managemet, of course, denied the allegations, and refused to speak in public or conduct interviews, which only fed the speculation that the band had indeed taken Beatles-influence too far. The backlash to the refusal to speak to the media, of course, caused the band to look arrogant, as well as even more guilty, as they did not face the negative press head on.
The critical backlash persisted for a number of years, apparently. After a dazzling debut in 1979, they finally fizzled out around 1982. As history goes, the band did reunite, and with changes, had success later on, so all was not lost.
But back to the Beatles ripoff history -- were you aware that the Knack had been accused of ripping off the Beatles to this extent? Was this well-known with consumers, not just industry insiders? It seems to have been taken quite seriously back in the day, to have ripped off the Beatles (ala a "Knuke the Knack" campaign, etc).
Anyone aware of this? Also, are there any other well-known cases of absolute RIP OFFS, not just influences, for other rock artists, where accusations have been this severe?