The Earth layer that is like plastic and moves slowly is the asthenosphere.

Here's why:

* Plastic-like behavior: The asthenosphere is a semi-solid layer located in the upper mantle. While it's solid, the intense heat and pressure allow the rock to behave like a very viscous fluid over long periods. Think of it like a very thick syrup or a really slow-moving glacier.

* Slow movement: This slow, viscous flow is responsible for the movement of tectonic plates, which ultimately drives continental drift and volcanic activity.

Let me know if you have any more questions about the Earth's layers!