http://www.newsweek.com/twitch-prime-crown-capsule-league-legends-free-legendary-shard-pc-account-1190450

At TwitchCon 2018, Twitch and Riot Games announced a new partnership to give League of Legends players access to exclusive loot. Players who link their Riot Games account with Twitch from today until Dec. 12 will get a brand new, in-game item: the Crown Capsule. Opening this pod in the Hextech Crafting menu will earn you a random legendary-tier skin shard. These skins, like Gentleman Cho’Gath or Corporate Mundo, cost 1,820 RP and have upgraded VFX and particle effects.

To transform the skin shard into a skin you can use in your collection, you’ll need to use essence to upgrade it to a skin permanent. If you’d rather not use the shard because you don’t like the skin, you can roll it with two others to get a random skin, or disenchant it for a couple of thousand essence.