An apparatus includes an impervious body, a sealing element; an energy source, and a trigger. The impervious body is configured to prevent passage of fluid therethrough. The sealing element is disposed about the impervious body. The energy source is operationally connected to the sealing element. The trigger is configured to transfer energy from the energy source to the sealing element. The trigger is activated, at least in part, by receiving a signal from a pump tool passing through an interior of the impervious body.