  We conjecture that the Higgs potential can be significantly modified when it
is in close proximity to the horizon of an astrophysical black hole, leading to
the destabilization of the electroweak vacuum. In this situation, the black
hole should be encompassed by a shell consisting of a "bowling substance" of
the nucleating new phase bubbles. In a binary black hole merger, just before
the coalescence, the nucleated bubbles can be prevented from falling under
their seeding horizons, as they are simultaneously attracted by the
gravitational potential of the companion. For a short time, the unstable vacuum
will be "sandwiched" between two horizons of the binary black hole, and
therefore the bubbles may collide and form micro-black holes, which will be
rapidly evaporated by thermal emission of Hawking radiation of all Standard
Model spices. This evaporation, being triggered by a gravitational wave signal
from the binary black hole merger, can manifest itself in observations of gamma
rays and very high energy neutrinos, which makes it a perfect physics case for
multi-messenger astronomical observations.
