Sometimes things go wrong.
Not sure what exactly happened to this Agave weberi, but last Fall it got this weird rotting disease that hit it high in the core and rotted through the growth spike. It may be OK but it sure is not pretty:
A couple of other plants are showing some weird effects that people have associated with treatments with miticides using a spreader sticker - which helps the miticide spread better along the leaf surfaces and better penetrate it, but it can also do weird things to the leaves that can become fused in weird places:
That is an Agave potatorum with some bad stuff going on in the core and below an Agave lurida (in all likelihood) with a less problematic but still fused leaf situation:
