Here's a short & sweet video that details how to defeat the optional world boss Grosse Tete in Clair Obscur: Expedition 33. It also includes where to find him and the special Picto you get as a reward.

For more guides for all the games you care about, head on over to https://www.gamerguides.com/

We have an in-depth Clair Obscur: Expedition 33 section that delves deep into many of the collectibles found in the game: https://www.gamerguides.com/clair-obscur-expedition-33/guide