  We investigate $p$ $\overline{\text{D6}}$ branes inside a flux throat that
carries $K \times M$ D6 charges with $K$ the 3-form flux quantum and $M$ the
Romans mass. We find that within the calculable supergravity regime where $g_s
p$ is large, the $\overline{\text{D6}}$ branes annihilate immediately against
the fluxes despite the existence of a metastable state at small $p/M$ in the
probe approximation. The crucial property that causes this naive conflict with
effective field theory is a singularity in the 3-form flux, which we cut off at
string scale. Our result explains the absence of regular solutions at finite
temperature and suggests there should be a smooth time-dependent solution. We
also discuss the qualitative differences between $\overline{\text{D6}}$ branes
and $\overline{\text{D3}}$ branes, which makes it a priori not obvious to
conclude the same instability for $\overline{\text{D3}}$ branes.

High Energy Physics - Theory