You give it to Charlie Brown, and he will sign Lucy's contract
You use the laser pen for cutting the window bars on Poptropica.
Great Pumpkin Island is the 15th Island of Poptropica, opened to general use in October, 2010. It stars the characters from the popular Peanuts comic strip in a short Halloween quest.----------------------------------------------------------There are no "cheats" as such on Poptropica, but there are solutions at the related question below. There are also special items in Poptropica at the related question.
Use the laser pen to cut the bars in the window.
If you mean the laser pen you use it to cut open the bars at the top on the building that electrocutes you on spy island to get the second spy.
You can't take it out, you can only use it when the island tells you to, and it will come into your hand to you can rescue the spy.
You go to the Spy Island and then you get to the top of the tower which has electricity jump on each platform when they are gone and when you reach the metal bars use the laser pen. (on the top)
Normally you get the pen when Linus gives you the invitation, because he has been writing a letter to the Great Pumpkin. You will then you go left of Main Street to have Snoopy gather leaves in the back yard. After the leaf scene and after Linus mails his letter, go left again and Lucy and Charlie Brown will be playing with the football. When Charlie says "Please find me a pen," click USE on the pen..
you drag it 2 the right
use the laser pen to vaporise the bars
your supose to use the laser pen
After you give him the pen, he is again tricked by Lucy. When they leave, pick up the football and take it left to Snoopy's doghouse. Use it to knock his flying helmet down from the tree.
After Snoopy gathers the leaves and Linus jumps into them, follow him as he mails his letter, and come back for his blanket. After he mails the letter, you can go left to where Charlie Brown and Lucy are using the football. Let Charlie Brown use the pen.