The History "Boogeyman" reduces Potence to 0. When you start playing, you can click the word Potence, and you will receive 10 XP. Move your cursor over Animalism and go back to Potence. Clicking it again will give you another 10 XP. If you click accept after your potence discipline is reduced to less than 0 (either -1 or -2) the discipline will vanish from your inventory forever.

The other clan that has this option is Gangrel.

Anda Gangrel -1 Animalism
Insectoid -1 Animalism
Boogeyman -1 Potence