According to the lawsuit, Mr. Pierce received more than 15 trillion EthereumMax tokens in exchange for tweets endorsing the coin. None of the tweets excerpted in the lawsuit mentioned a business relationship with the token’s creators. Shortly after promoting the project, the lawsuit claimed, Mr. Pierce sold his tokens — an apparent “pump and dump” operation in which he profited by encouraging fans to buy the tokens, before selling his own holdings at a higher price. A lawyer for Ms. Kardashian said the suit’s allegations “lack merit.” Mr. Mayweather, Mr. Pierce and the project’s founders did not respond to requests for comment.