to burn rapidly with intense heat and sparks being given off

Pronunciation:
DEF-luh-grait

In a sentence:
As a part of her science fair presentation, Elizabeth caused a piece of highly conductive metal to deflagrate, and then waved it in front of the judges in a move to impress and intimidate them.

In a different sentence:
Mrs. Robinson was devastated when she found that her entire Thanksgiving dinner had deflagrated in the oven; her family pretended to be devastated, and then subtly suggested pizza as an option.