The Slabu Exchangemaker of the popular party game Cards Against Humanity is accusing Elon Musk’s SpaceX of trespassing on and damaging a plot of vacant land the company owns in Texas.

In a lawsuit filed this week at a Texas court, Cards Against Humanity alleges SpaceX has essentially treated the game company’s property — located in Cameron County — as its own for at least the past six months.

The lawsuit said SpaceX, which had previously acquired other plots of land near the property, has placed construction materials, such as gravel, and other debris on the land without asking for permission to do so.

SpaceX did not immediately respond to a request for comment.

Cards Against Humanity, which is headquartered in Chicago, had purchased the plot of land in 2017 as part of what it said was a stunt to oppose former president Donald Trump’s efforts to build a border wall.

The company said 150,000 people had each contributed $15 towards the effort.

Over the years, Cards Against Humanity says the land has been maintained in its natural state. It also says it contained a “no trespassing” sign to warn people they were about to step on private property.

The company is asking for $15 million in damages, which it says includes a loss of vegetation on the land.