We have a bit of conundrum with the Moon. Its usual interpretation often has to do with hallucinations, insanity, wildness...but it also relates to dreams, fantasy, artistic talent, creativity, psychic ability, romance. This makes interpreting the reverse a bit troublesome. Is it positive or negative? Let's see what we can work out.
1) Opposite: trying to figure out the opposite of the Moon is problematic. Logically, it should be "The Sun." But we already have that card. So let us say, instead, that it is the "Dark of the Moon." In this instance, I would interpret the Moon at its very worst, giving its milder interpretations to the upright.
By the light of the Moon, we can still find our way - even if wild things do happen by that light. When the Moon is dark, however, dark things happen. We might well say that things are not merely wild, but primitive. Criminals lurk in the dark, shady folk with dark purposes and intents. Sexual predators instead of romance, artistic talent used to hurt and destroy. Evil fantasies and dreams. Here is the stalker, the person who wants to scare and harass.
This interpretation would probably include a bad psychological time. If the querent suffers from any problem or has someone in their family suffering through such a problem (depression, bi-polar disease, substance abuse) they are going to be going through a dark time with it. It's going to be a long dark night of the soul.
2) Blocked: The energy of the Moon is that of chaos. It can be insanity or artistic genius, but either way, it is restricted. Blocked suggests a writer's block, perhaps a sexual block, even a block put on that insanity (medication that dulls the mind?). The block might be physical (bars on the window!), or just self-restraint. This is not order, so much as a lock on the door, keeping the chaos, freedom, and wildness outside.
There may be calm with this blockage - but it is artificial. The chaos has not been removed or corrected, only prevented. Bars protect the person from the wild, but the wild still calls to them. So, in this case, crime is prevented, but not stopped. Depression, etc. are held off, but not cured.
3) Upside-down: Turn the card upside down and the creatures are not gazing up at the Moon - the Moon gazes up at them instead. This suggests that what rules and commands the wild is no longer in charge. Base as these instincts may be, they do have a gut feeling that they are following. It's certainly topsy-turvy for the light to be looking up at them, for them to be in charge instead.
It is out of primordial ooze, out of chaos, that order comes (the Sun will follow the Moon), but upside-down, it suggests that order is moving into chaos instead. That even the guiding light of the moon has been subjected, and only the primitive reigns - unchecked, directionless, with no purpose or hope of coming to an end.
This is the sort of interpretation one might find for revolutions and riots, for countries melting down into political turmoil with no path to peace in sight. On a more personal level, you're likely to get this interpretation for a complete mental breakdown or a merciless plummet into the worst depths of drug addiction. There is no civilization. Men and women are ruled entirely by their animal natures. Complete anarchy.
Curious about this card when upright? Go to our Tarot Card Meanings.