Nothing, at that point. Go back to the museum where you will receive a package.
The message will summon you to meet the Museum curator on Early Poptropica island. Fly there in the blimp to receive a valuable key.
Nothing, when you find it. You will need it later in the game. When you are getting past Black Widow's guards, the key card opens the door to her trove of stolen art, which is the final battle of the island.
When you get past the Widow's guards, you can use the key card.
Back at the museum, you have an unexpected package from the travelling curator of the Museum.
You go back to the museum, where a package is waiting for you. Scanning it will give you a message that sends you off on a brief visit to another island.
Go back to the museum, where you have a package waiting. The key card is used later.
You will travel to Early Poptropica to meet the curator at the Pop Art Museum.
you go to the art musem
When the Black Widow catches you , you will have to pass the guard and at top you will use your card
You do this near the end of the game, when you are in the lair of the Black Widow.
Use the key card to open the treasure room and battle the Black Widow. (see related questions)
You only use the Black Widow key card at the end of the island, to open the sliding doors in her secret hiding place.
Nothing right away. Eventually you get into the black widow's lair and use the card to enter her trove of stolen art.
When you are in the Black Widow's secret headquarters, and go past the guards, there is a door with a lock requiring the Black Widow card. Press USE on the card and it opens the door to where you fight the Black Widow.
You use it late in the game to reach the Black Widow in her trove of stolen art. Its use will be immediately obvious from the card-reader on a door you encounter.
It is the last part of the island, when you have discovered the stolen painting and get kidnapped by the Black Widow. Get past her guards and use the key card to begin the final battle.
The Black Widow key card is dropped by the art thief (shady guy) when he makes his escape by boat.
The key card is used later in the game in the Black Widow's lair. Save the key card and return to the museum.
After you get the key card, return to the museum for the package there. You will soon have the key to the Inspector's house, and the key card is used sometime later. It opens a guarded room where the Black Widow keeps her stolen art.