No sooner do I mention the caterpillars staying on milkweed to transform, and several decide to j-hook on plants. I clip the leaves and hang them up so remaining caterpillars can't harm them. This process of transformation, once started, only takes a minute or so and I usually miss the actual transformation, but this time I saw it starting and my camera was handy. The real clue that it is about to happen, is when the antenna go completely limp.
A lot of movement takes place to discard that shed skin. Then the pupa settles down and takes on the familiar chrysalis shape.