Social media startup Fizz is suing grocery delivery giant Instacart and party planning app Partiful for trademark infringement, the company announced on Thursday. Earlier this week, Instacart launched a new drinks and snack delivery app for parties called Fizz and announced that Partiful had integrated Fizz directly into its platform.

Fizz Social, a college-focused startup, alleges Instacart’s new platform infringes on its brand. A startup marketing to Gen Z on college campuses filed a lawsuit this week alleging that Instacart engaged in federal trademark infringement and unfair competition by naming its new group ordering app “Fizz.

Instacart’s new party-centric app Fizz, launched on Tuesday, could go flat following a trademark lawsuit filed on Wednesday by Fizz Social Corp. in a California district court.