The rivalry between Beats and its former ally Monster just got particularly bitter. Monster is suing Beats, its founders (Dr. Dre and Jimmy Iovine) and HTC for allegedly tricking it into giving up one of its best-known headphone lineups. According to the lawsuit, Beats committed fraud when it acquired the Dr. Dre audio range through HTC's investment. It supposedly repurchased enough stock after the HTC deal that it could sever its ties with Monster due to an ownership clause, leaving the latter high and dry with no real warning. Monster also believes that its ex-partner was misleading when it claimed in September 2013 that there was no "liquidity event" (that is, a major transaction) coming within one to two years -- Apple's acquisition of Beats clearly involved a lot of money trading hands. If Monster chief Noel Lee had known that the Apple buyout was looming, the lawsuit reads, he wouldn't have reduced his stake in Beats and missed out on the resulting windfall.