Twisted double bilayer graphene (TDBG) is comprised of two Bernal bilayer graphene sheets with a twist between them. Since the band structure of each bilayer depends on the electric field perpendicular to the plane, the Moire band structure of the double bilayer system can also be controlled by perpendicular electric field. When the twist angle is close to 1.3 degrees, the result is a van der Waals system hosting flat electronic bands with non-trivial topology, where in-situ tunability of the band structure makes it especially well suited to experimental interrogation. Indeed, using gates to navigate through the electronic phase diagram of a TDBG sample, many of the correlated phenomena that are observed in other graphene-based van der Waals structures may be found also in this system, from anomalous Hall-like hysteresis implying spontaneously broken time reversal symmetry, to superconductivity when the TDBG is placed next to a WSe2 dielectric. In addition, this talk will present a phenomenon in TDBG that has not be reported in any other van der Waals system to our knowledge, and for which we do not yet have a microscopic explanation: an extremely strong dependence of the resistance on in-plane magnetic field, isotropic within the plane but far stronger than the dependence on out-of-plane magnetic field. The overall phenomenology of the effect will be described, and possible routes to an explanation discussed.