The shirt was awesome! It looked like it was about a nanometer thick, and fit like a second skin, showing off Jacob's muscular torso. The high tech fabric, designed for use in climate control systems, only moved heat one way, but the recent heat wave turned it into an instant fashion hit.
On the train to Selfoss, Jacob was too hyped about his date with Jeff to notice a small blob of his shirt dripping off the hem falling to the floor like a blob of black mercury. He barely registered the girl's “eewww” behind him as the train accelerated. In fact, Jacob first noticed something amiss when he felt a brush of warm air on his belly button.
Looking down he noticed a large split in his shirt from his belt buckle to the bottom of his rib cage, while the sides of his shirt drooped down his legs like hot taffy. Jacob, remembering he was surrounded by dozens of people, blushed his humiliation. Aghast onlookers became more aghast, as the slight increase in his skin temperature triggered a state change and the taffy goo splashed off him in a pool of liquid polymer, exposing Jacob's torso completely. Fortunately, the shirt-stuff only stuck to itself, leaving Jacob and the other passengers dry and stain free.
The train reached his stop. Jacob, suppressing his embarrassment, climbed out of the car. Upon seeing Jeff he grinned broadly saying, “good thing you wore boxers under those pants!”