The feature formed when lava cuts across rock layers and hardens is called a dike.

Here's why:

* Dike: A dike is a sheet-like intrusion of igneous rock that cuts across existing rock layers. It forms when magma forces its way into cracks and fractures, cools, and solidifies.

Here are some other features that might be confused with a dike:

* Sill: A sill is also a sheet-like intrusion of igneous rock, but it is parallel to the existing rock layers.

* Batholith: A batholith is a large, irregular-shaped intrusion of igneous rock that is often found in mountain ranges.

Let me know if you have any other questions!