On a day when all the pre-match headlines centred around Elliott Whitehead's return to Odsal after his acrimonious departure earlier this year, it was the boot of Bosc that snatched the victory for the Dragons in a game they looked well out of at half-time, trailing 18-4.
Keith Lulia went over twice for the Bulls but it was not enough as tries from Mathias Pala, Jamal Fakir, Brent Webb and Ian Henderson handed the French visitors the win.
The Bulls were unchanged from last weekend's victory over Wakefield but the Dragons - without influential duo Morgan Escare and Scott Dureau - showed five changes to their line-up as they sought their second win in six games.
In contrast, the home side have been in good form of late, and they took the lead in the fifth minute when Lulia - who is set to return to the NRL with Wests Tigers at the end of this year - took a superb ball from Danny Addy to crash over.
The Dragons hit back as a neat kick from the returning Webb saw Pala ground the ball in the corner, but Bosc missed the conversion.
The Bulls struck again after 15 minutes, full-back Brett Kearney starting and finishing a fine sweeping move to go in under the posts.
The hosts extended their lead to 14 points seven minutes later. After Pala had knocked-on from a routine scrum, Lulia went in for his second as he shrugged off the attentions of three Dragons defenders in the corner.
The Dragons grabbed the first score of the second period to bring the game alive once more.
A magnificent break from Lopini Paea laid the platform before Fakir did the rest to make it 18-10.
The Dragons had all the momentum as the second half wore on, and Whitehead came desperately close to scoring against his former club before the visitors finally made their pressure tell in the 61st minute when Leon Pryce's superb inside ball to Webb brought the Bulls' lead down to just two.
The see-saw nature of the game continued as Pala spilled Luke Gale's chip and after a couple of near misses, Kearney sent Adrian Purtell through a gap and over the try-line.
The big moment arrived in the 73rd minute though, when Kearney was sin-binned for holding down Whitehead in the tackle.
Henderson, another former Bradford man, took full advantage by scooting over from dummy-half to level it up.
And Bosc stole it with just three minutes left on the clock to put a serious dent in the Bulls' play-off ambitions.