On Sunday night, Elon Musk, tweeted out a cheeky reminder that SpaceX’s autonomous drone ships are still pretty one of a kind. Responding to a story by The Verge announcing that “The world’s first crewless cargo ship will launch next year,” Musk shot the publication a little virtual side eye with a picture of the drone ship, Of Course I Still Love You.

The SpaceX CEO has a point; Of Course I Still Love You and its sister ship Just Read the Instructions are GPS-guided barges that operate off the coast of Florida and California, respectively. Of Course I Still Love You was first successfully used in April of 2016 as landing pads for SpaceX’s Falcon 9s. They’re big; around 300 feet by 100 feet, and are equipped with wings that can extend the landing area by 170 feet.

The drone ships have been instrumental in SpaceX’s quest to reuse its Falcon 9s. Each drone ship’s ocean position gives a Falcon 9 more of a chance at landing, because the rockets don’t have to travel all the way back to their land-locked launch sites. With the drone ships, they can save considerable fuel, and potentially use it instead to properly maneuver a landing or simply make it to a drone ship, instead of hurdling to a watery grave. For some of SpaceX’s heavy-payload missions that need a lot of fuel, the drone ship can be their only option for landing — and therefor rocket recovery.

Each drone ship’s name is taken from sci-fi author Iain M. Banks’ Culture novels, specifically, the sentient ships in The Player of Games.