Extreme colour change from stress
Just thought this was (slightly) interesting. It's Jayo's "Easy ABS" - weird stuff, not really like ABS at all. It's very tough, but with poor temp resistance. If you bend it in half, if changes colour very dramatically
Most plastic lightens and becomes "milky" when stressed.
I've seen that a ton with injection molded plastic, but I don't know if I've ever seen that happen on a printed part before. My prints usually break before deforming enough to get discolored.
Real ABS turns white/grey too, from both stress and acetone (in liquid form, vapor does not seem to discolor it).