Cosmic Skateboard
Summons an alien skater 'Kickflips are a lot easier in Zero-G!'
How do you do, fellow humans?
5Dropped by
how the pet behaves
It does nothing in a fight, but it is one of the better animated pets in the game. The skater rolls along the ground beside you and only switches to the rocket board when you jump or pull ahead, so instead of blinking to your feet the way most pets do it visibly chases you down. Worth keeping out purely because it reacts to how you move.
getting it is the hard part
It only exists in Master Mode, and only off the Martian Saucer. The event will not come to you either: after Golem you have to wander the outer thirds of the map until a probe scans you, then let it escape rather than shooting it down. The saucer is the event mini-boss, so every attempt is a real fight against something that can kill a fresh Hardmode character in seconds. Build the arena first and treat the pet as a bonus on top of the drops you actually want.
the joke
The buff line is a 30 Rock gag, an adult trying to pass as a teenager while carrying two skateboards.