Skins

Skins (main)
Skins in Bonetale are most of the time used for cosmetic reasons, other reasons are completion or unlocking maps, music or characters. Skins require a challenge in order to complete.

Challenge 1: actions with frisk
as example take muffet of asriel. these are skins that you unlock by doing certain actions with frisk.

Challenge 2: themed stuff
as example take papyrus, alphys or MTT, these are skins you unlock using characters with their respective attacks.

Challenge 3: miscellaneous.
as example take Gaster, Sonic, Woloned or Mario, these are skins that you unlock with secrets and that do not have a lot to do with characters or mechanics.

Challenge 4: Events
So far, the Underfell event is the only event that is actually in the game, and can be played for every character once the player completes Demonic mode with said character. Completing the Underfell event will unlock attack skins, character skins (and in Sans' case, a new Bad Time colour).

Challenge 5: Cases
Since the Multiplayer Update, cases were added to the game, allowing players to potentially unlock character skins, attack skins, gold and even nothing (can only be obtained from the Easy case). There are four categories of cases, which are named Easy, Medium, Hard and Demonic (after the various playable difficulties) and have to be bought with gold.

(Note that any skin can be unlocked with the use of save editing)