Some fanart that I drew for McSteel.

As far as I know, Cassidy's breasts tend to grow to a tremendous size whenever she becomes overly-excited by certain stimuli. Meaning that if she were ever frightened, aroused, enraged, etc. by a certain person or thing (in this case a rather large spider), then her bosom would easily expand to colossal proportions; usually within a matter of moments.

As to why her body subconsciously does this is unknown. However, my theory is that her sudden and involuntary breast expansion ability acts as some kind of defense mechanism. A biological reflex, if you will; designed to scare off predators by making herself seem larger than she really is. Whether or not this theory is true however, has yet to be proven.

Maybe I should see about getting a bigger spider, so as to better test my theories. X3

Cassidy copyright McSteel
artwork copyright SatsumaLord