We construct a small,
hyperbolic 3-manifold M with the property that, for any integer g ≥ 2, there are
infinitely many separating slopes r in ∂M such that the 3-manifold M(r) obtained by
attaching a 2-handle to M along r contains an essential separating closed surface of
genus g. The resulting manifolds M(r) are still hyperbolic. This contrasts
sharply with known finiteness results on Dehn filling and with the known
finiteness result on handle addition for the cases g = 0,1. Our 3-manifold M
is the complement of a hyperbolic, small knot in a handlebody of genus
3.