A Tesla Inc. investor has sued over Elon Musk’s $2.6 billion-valued pay package in the Delaware Court of Chancery, calling the stock option a “massive, unfair and unprecedented” gift that would make the car manufacturer’s CEO one of the richest public-company executives in the world.

In a recently unsealed complaint, Tesla shareholder Richard Tornetta said the 10-year compensation plan could balloon to more than $55 billion if the Palo Alto-based company continues to grow at its current clip.