In the early morning of the 8th of December on the day of Mars reaching opposition, The Moon moves in front of (occults) Mars.
Timing is roughly…
Disappearance: 04:58 UT.
Mars disappears near crater Grimaldi.
Reappearance at the bright limb, by Mare Australe: 05:57 UT.
The timings shown are as seen from my location, so your timings may be slightly different from these.
The speeded up animation below, created using Stellarium, shows what we might be able to see at disappearance and reappearance.