Create a new Scene

Add an Area3D as the root

Rename it to Spikes

Save the scene as Spikes

Drag the spikesLarge.obj into the scene

Reset the position to 0,0,0

Set the scale to 1,3 on X, Y and Z

Rename the Node to Model

Add a CollisionShape3D with a BoxShape3D collider

Resize it to fit the spike model.

Add a Script to the Spikes root node.

Connect the body_entered signal

Add spikes to the level. Touching them will reset the level.