Fermi liquid behavior and colossal magnetoresistance in layered <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>MoOC</mml:mi><mml:msub><mml:mi mathvariant="normal">l</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

A characteristic of a Fermi liquid is the ${T}^{2}$ dependence of its resistivity, sometimes referred to as the Baber law. However, for most metals, this behavior is only restricted to very low temperatures, usually below 20 K. Here, we experimentally demonstrate that for the single-crystal van der Waals layered material $\mathrm{MoOC}{\mathrm{l}}_{2}$, the Baber law holds in a wide temperature range up to \ensuremath{\sim}120 K, indicating that the electron-electron scattering plays a dominant role in this material. Combining with the specific heat measurement, we find that the modified Kadowaki-Woods ratio of the material agrees well with many other strongly correlated metals. Furthermore, in the magnetotransport measurement, a colossal magnetoresistance is observed, which reaches \ensuremath{\sim}350% at 9 T and displays no sign of saturation. With the help of first-principles calculations, we attribute this behavior to the presence of open orbits on the Fermi surface. We also suggest that the dominance of electron-electron scattering is related to an incipient charge density wave state of the material. Our results establish $\mathrm{MoOC}{\mathrm{l}}_{2}$ as a strongly correlated metal and shed light on the underlying physical mechanism, which may open a new path for exploring the effects of electron-electron interaction in van der Waals layered structures.