Katharina Weischede started making slime, a stretchy kids' toy made from glue, water, borax and food colouring as a hobby, but then turned it into a business called Slime Princess.
But when she tried to trademark the name, she came up against opposition from American media company Viacom, which owns kids' channel Nickelodeon.
For more than a year, Katharina has been embroiled in a battle with Viacom, which had trademarked the word "slime" according to the NZ Intellectual Property office.
Nickelodeon is known for dunking celebrities in buckets of green slime at its awards show Nickelodeon Kids' Choice Awards.
Plucky young Katharina was determined to fight the trademark dispute.
She raised more than $10,000 through a Givealittle page to help with her legal fees and also set up a petition, which received more than 1000 signatures from supporters backing her trademark claim.
Then last week, Katharina got the reprieve she had been looking for when Nickelodeon decided to withdraw its opposition.
A Nickelodeon spokeswoman told the Weekend Herald: "We review all these on a case by case basis and have determined that Slime Princess will not impede upon our trademark of slime in New Zealand."
In a letter to the Intellectual Property Office commissioner dated April 16, Viacom's lawyer asked for the opposition to be withdrawn and that "the opponent does not require an order for costs".
"We admire Katharina's entrepreneurial spirit and wish her the best of luck," the spokeswoman added.
Katharina's family lawyer Alex Lee said they were pleased Nickelodeon had withdrawn its opposition.
"We have maintained that Slime Princess is a unique brand and trademark that does not cause any confusion for the audience and marketplace," Lee said.
"The withdrawal has enabled a 12-year-old entrepreneur to believe that it is possible to pursue and reach her dreams."
Katharina's mother Maricel Weischede said the family was very pleased with the victory.
"The Slime Princess is very happy. She now can move on. Things that were put on hold because of the trademark issue, can finally push through," she said.
Weischede said Katharina has had many sleepless nights during the almost year-long battle.
"We would like to thank everyone who supported the Slime Princess and our family," she said.
"One [piece of] advice I'd like to give to parents is to let your children explore and support them. It was easier for us to just back out then, it would be more cost-efficient, it would be less stressful, but if we did that then what would it teach our daughter?"
Weischede believed Katharina had inspired children and adults alike to "fight for what you believe in".
Katharina herself said she was "overjoyed" and still found it hard to believe she had "won my battle with the giant".
"I still believe there is goodness in everyone, and it's true. There is goodness even in the giant, and now the battle is over," she said.
Nothing can stop Katharina now - she is turning her attention to publishing a Slime Princess book she has written and then opening a Slime Princess-themed restaurant.
