  In this article, we give a concrete description of the underlying reduced
subscheme of the Rapoport--Zink spaces for spinor similitude groups with
special maximal parahoric (and non-hyperspecial) level structure. Moreover, we
give two applications of the above result. One of which is describing the
structure of the basic loci of mod $p$ reductions of Kisin--Pappas integral
models of Shimura varieties for spinor similitude groups with special maximal
parahoric level structure at $p$. The other is constructing a variant of the
result of He, Li and Zhu, which gives a formula on the intersection
multiplicity of the GGP cycles associated codimension $1$ embeddings of
Rapoport--Zink spaces for spinor similitude groups.
