In plants, it is part of the mesophyll, where it forms a layer next to the palisade cells in the leaf.
The spongy mesophyll's function is to allow for the interchange of gases (CO2) that are needed for photosynthesis.
[1] In the alphonso mango variety, this problem is particularly common, giving soft, white, 'corky' tissue.
Spongy tissue is also a type of animal tissue which contains smooth muscles, fibrous tissues, spaces, veins, and arteries.
An example is the corpus spongiosum penis.