From the author's README on Thunderstore

Baldee x Disney Alien Cap

Author: не я

A yellow three-eyed alien cap for skate. via ReSkate.

Features

Custom hat mesh and base-color texture.
Selectable headwear cosmetic: Alien Cap (Own_Alien_Cap).

Installation

Install through the ReSkate mod browser and enable the package. Restart the game, then select the cap in the headwear wardrobe.

For manual installation, extract the package into its own folder inside your ReSkate Mods directory. The folder containing layout.toc must also contain Win32 and initfs_win32.

Compatibility

Built with ReSkate Studio and tested in game by the uploader. Requires the supported ReSkate game build. Does not require other cosmetic packs.

Credits

Unofficial fan-made cosmetic. Disney/Pixar character references belong to their respective owners. Not affiliated with or endorsed by Disney, Pixar, EA, Full Circle, or ReSkate. Original source model and texture authors are not specified in the supplied files.

Install Bladee x Disney Alien Cap

You need ReSkate and your own copy of skate. on Steam.

Open ReSkateLauncher.exe and go to MODS.
Search for Bladee x Disney Alien Cap and click install. The launcher also installs anything it depends on.
Press PLAY. In game, the MODS tab of the ReSkate menu (Insert) turns it on and off.

Or install it by hand: download the .zip and drop it on the launcher window, or unzip it into its own folder in Mods\ beside Skate.exe.

Maps show up in the ReSkate menu's level list. To join a server running a custom map, you need the same map installed. If the game won't load after installing, see known issues.

skatemods doesn't host or review this mod. The download comes straight from Thunderstore. Only install mods you trust, because scripts can run code.