In this work, we investigate the dynamical influence that external, triaxial and tumbling halos may exercise on disks that may lie embedded in them. Such halo configurations are noted in cosmological simulations, to typically rotate about their short axes, with tumbling periods of the order of a Hubble time. Thus, such halos can exert a slowly changing external torque on disks, affecting disk evolution in the process. Another source of complex dynamical effects is the probable misalignment between a disk and a triaxial dark halo. In this work, we conduct a series of experiments in which we explore the effect of a slowly changing quadrupolar tidal potential on N-body models of our Galaxy and M31; our particular aim is to check if this can induce disk structures such as bars, spirals and warps!