Just as nilpotent orbit closures in simple Lie algebra, nilpotent Slodowy slices play a significant role
in representation theory and in the theory of symplectic singularities. In other direction, it is known that there
appear as associated variety of W-algebras. It is also known that they appear as the Higgs branches of the
Argyres-Douglas theories in 4d N = 2 SCFTs. In my talk, I will explain how these facts are related, and how
we can use this to study collapsing levels for W-algebras, and related conjectures. This is based on a joint work in progress with Tomoyuki Arakawa.