Strange Living Shapes
A rare and special long cycle. The result is either to void the game or the infinite repetition is forbidden by some kind of superko rule.
Moonshine life refers to a position where a (seemingly) dead group with a false eye in ko cannot be captured, because the owner of the group has an unlimited number of unremovable ko threats. On the top left the White group is alive in moonshine life, because the top right (double ko seki) generates unlimited ko threats.
Beginners who do not understand the difference between strings and groups may find the following group confusing because no string of stones completely surrounds a single eye.
If a group seems alive to you but you are unsure where it's axiomatic "two eyes" are, you should consider filling in false eyes to connect the group.
Now we see a typical two-eyed living group. Note that actually playing a move like this on the board is unnecessary.