To burst into flame; take fire, either literally or figuratively.
The Century Dictionary (Public Domain)
Use "conflagrate" in a sentence
"Since your last remark provides nothing other than a sarcastic "thanks" that wrongly suggests I was lecturing you, I will try not to conflagrate this incendiary issue any further."
"You are likely to conflagrate … spontaneously … and you are headed for my place?"
"Drengenberg, who says he plans to put up both real and artificial trees in his home this year, has a few tips for people who want a real tree, but who don't want to see it conflagrate:"