  We observe stable holes in a vertically oscillated 0.5 cm deep aqueous
suspension of cornstarch for accelerations a above 10g. Holes appear only if a
finite perturbation is applied to the layer. Holes are circular and
approximately 0.5 cm wide, and can persist for more than 10^5 cycles. Above a =
17g the rim of the hole becomes unstable producing finger-like protrusions or
hole division. At higher acceleration, the hole delocalizes, growing to cover
the entire surface with erratic undulations. We find similar behavior in an
aqueous suspension of glass microspheres.
