Any substance that swells on exposure to heat, thus increasing in volume and decreasing in density.
abnormally distended especially by fluids or gas
"hungry children with bloated stomachs"
"he had a grossly distended stomach"
"eyes with puffed (or puffy) lids"
"swollen hands"
"tumescent tissue"
"puffy tumid flesh"
That becomes swollen, especially upon exposure to heat