Arcane Ablation

You touch a piece of worn armor or clothing and imbue it with magic. The creature wearing this imbued item gains 4 temporary hit points. When these temporary hit points are exhausted, at the start of the creature’s next turn it will gain hit points equal to 1 hit point less than the previous amount gained from this spell (for example, from 4 to 3), until no temporary hit points would be gained and the spell ends. Temporary hit points from this spell are lost when this spell ends.

At Higher Levels. The initial temporary hit points increase by 1 for each spell slot level above 1st.

Source. Kibbles' Compendium of Craft and Creation by KibblesTasty