Territorial Rust Monster

Whenever Territorial Rust Monster deals damage
to one or more creatures, or is dealt damage by
one or more creatures, you may distribute up to
X erosion counters among all Equipment
attached to those creatures, where X is
Territorial Rust Monster's power. (Permanents
with one or more erosion counters on them have "At
the beginning of your end step, if this permanent has
five or more erosion counters on it, sacrifice it.")