Paranormal Party Starter is a hat accessory available in the avatar shop for free until November 2, 2022. The accessory is a white ghost wearing black wireless headphones, as shown in the image below.

The Black Adam Hawkman Helmet is a hat that comes under "Accessory" in the Roblox shop. It was updated on October 18, 2022, and has a butter-ish yellow color and a very creepy look.

Robux is one of the ways that Roblox Corporation makes money, so it would be erroneous to think you could get them for free.