This article is about the Ladybug Miraculous. You may be looking for another Ladybug or Miraculous.
Major Spoiler Warning This page contains major spoilers from an episode(s) that has not aired in the US yet.
I used to think that maybe [Ladybug] was a scientist who got stung by a radioactive ladybug while strolling at the Cité des Sciences. But the more I think about it, the more I believe it's actually the earrings that help Ladybug to transform, so the whole bug-bite theory kind of went out the window.
The Ladybug Miraculous is a pair of earrings that, whenever Tikki inhabits them, transform the wearer into a ladybug-themed superhero, with the power of creation (good luck). The earrings are currently owned by Marinette, who uses them to turn into Ladybug.
In general, the earrings are circular with a smooth surface and a silver lining. When Marinette isn't Ladybug the earrings are black. However, when Tikki goes into the earrings while Marinette is transformed, they become red with five black spots in a quincunx pattern. As Marinette starts running out of power, the earrings make a beeping sound and the dots start disappearing one at a time as an indication of how much time she has left.
The Ladybug Miraculous grants its wielder incredible powers of speed, endurance, and strength. Its special weapon is an unbreakable yo-yo, which can be utilized as both a weapon and a communicator. Its special superpower is called the Lucky Charm, giving the user the ability to create a useful object in order to obtain their goal, like defeating a villain. As long as the superpower isn't used, the wielder can remain transformed indefinitely. However, as soon as the superpower is used, the wielder loses power and the transformation usually wears off in five minutes. The earrings also has the ability to give the wielder the costume they truly desire.
The Ladybug Miraculous also can purify anything "corrupt or malignant." Using the yo-yo, the holder traps the infection, an infected creature, or an infected object, and the yo-yo cures it. When the yo-yo opens, the infection is gone, and if there was an infected animal or object, it is healed or clean. The person can use the Miraculous' purification power on various things, like akumas created with the Butterfly Miraculous or an unknown black substance seen in fourth issue of Miraculous Adventures.
If the Ladybug Miraculous and Cat Miraculous are used together while also using a special invocation, the holder will achieve ultimate power. The person wielding them can make a wish that can alter reality. However, because the universe must maintain balance, every action has a reaction; for instance, a wish to become human would result in someone losing their humanity.
After Tikki consumes one of several special potions, or an eatable made with one, and the wielder transform, they are able to unlock power-ups, an additional specific ability granted by each potion. So far, only seven potions has been shown, each with a unique color:
The green potion transform Tikki into "Aqua-Tikki" and grants the wielder the ability to breathe underwater, and improve their swimming capability with flippers on the feet.
The light blue potion grants the wielder ice related abilities, and the suit gains a pair of skates to move freely on ice. In this form, the round spots on the suit and the Yo-yo are hexagons.
In the theme song, the Ladybug Miraculous are in the raised center of the Miraculous jewelry box with the Cat Miraculous, both of their sections creating a yin-yang symbol inside the box.
The Ladybug Miraculous is in the yin section (like in every yin-yang symbols, there’s also both of them in each). Some of the things that yin represents is coldness, darkness, passiveness, and intuition (which interprets the Cat Miraculous).
Ladybugs are known to be symbols of good luck, protection, and love.
Ladybug's legacy is over 5,000 years old, as revealed in "The Pharaoh".
Both the Ladybug Miraculous and the Goat Miraculous are so far the only known Miraculouses that has two pieces.
The user needs to be wearing both earrings for the transformation to work.
As seen in "The Dark Owl", if one of the earrings are taken, the suit will slowly dematerialize, though the Yo-yo remain.
When the left earring was taken, the dematerialization began with the right side of the mask and the right hand, showing Marinette's bare skin.
In "Troublemaker", the left earring was taken, and the dematerialization began with the left side of the mask, both forearms, and both shins. Additionally, a high pitch beeping was emitted from the earrings. As the suit dematerialized, Marinette's body, excluding the face, was covered with pink energy. When the earring was returned, the missing parts completed themselves, and the beeping stopped.
In early concept for the series, including before kwamis were created, the earrings gave pure luck to its wearer. However, as Thomas Astruc explained, "it only works when [the wearer uses] it for others. Otherwise it backfires."
Because broadcasters believed pure luck as a power was "too abstract for kids," Thomas figured out a different superpower, Lucky Charm. 
The design of the earrings was different in the Ladybug PV and early CGI animation. In them, the earrings had gold outlines around the edges of the earring and the black spots.
In "The Pharaoh", Ladybug gives Pharaoh a fake pair of earrings that more closely resemble the earlier design.
Thomas Astruc stated that he might include previous Ladybugs into the show if he finds a good story for them.
For a staged battle for Mr. Damocles as the Owl in "The Dark Owl", Marinette creates a fake replica of the Ladybug Miraculous, which she later uses to trick Mr. Damocles' akumatized form and Hawk Moth.
In the NYCC 2016, the Ladybug Miraculous seems to have other magical abilities. These abilities seem to be related to objects known as the Stone of the Sun, the Stone of the Moon, the Pearl of the Sea, the Pearl of the Heart, and the Pearl of the Mysteries.
Stone of the Sun - Flying power
Pearl of the Mysteries - Infinite Lucky Charms
Pearl of the Heart - Cure the akumatized
Pearl of the Sea - Breathe and swim underwater
Stone of the Moon - Fly and breathe in space
However, Thomas later confirmed on Twitter that the Pearls and Stones are a concept that won't feature in the show anymore.