Why does the spoon look bent where it enters the water?

The spoon looks bent because light bends, or refracts, when it travels from air into water, since light moves at a different speed in each material. Your eyes assume light always travels in a perfectly straight line, so when the path bends at the water's surface, the part of the spoon underwater appears shifted from where it actually is.

The water isn't boiling, since nothing in the setup is heating it, and the spoon definitely isn't melting, since metal spoons keep their shape in cool water, so neither of those explains the visual trick at all.

This same bending of light is what makes swimming pools look shallower than they really are, which is why lifeguards are trained to always check the actual depth before diving.