Blood Pact

You perform a blood magic ritual involving two creatures of the same creature type as the other (one of these creatures can be yourself). Each target must remain within range for the entirety of the spell’s casting time. An unwilling target can make a Constitution saving throw, resisting the spell on a successful save.

When the spell is complete, the vital essence of one target is magically transferred to the other. For the spell’s duration, one of the spell’s targets has its current and maximum hit points reduced by an amount of your choosing, up to a maximum of 10. This effect cannot be used to bring a target’s hit points to below 1. The maximum hit points of the other target then increases by the same amount for the spell’s duration.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the maximum amount of hit points that can be transferred increases by 10 for each slot level above 1st.