  We consider several properties of a set of anti-D$p$-branes in the presence
of orientifold $p$-planes in type II theory. This system breaks all the
supersymmetries of the theory, but is free of tachyons. In particular, we
center on the case of a single anti-D$p$-brane stuck at a negatively charged
orientifold $p$-plane, and study its strong coupling behaviour for $p=2,3,4$.
Interestingly enough, as the coupling increases the system undergoes a phase
transition where an additional antibrane is created. We conclude with some
remarks on the limit of large number of antibranes on top of orientifold
planes.
