Graft

Source Howl of the Wild pg. 218 2.0
An item that has the graft trait is a living tissue sample that has been implanted into a host. It’s permanently a part of the subject’s body and reduces the number of items that creature can invest per day by 1. Each graft has the invested trait to indicate this limitation—a graft is like an invested item that the host creature has no choice but to invest. If a creature gets a new graft when their limit on invested items has already been reduced to zero, the host body rejects the graft. Once fully implanted, a graft cannot take damage separately.

If a graft is ever severed from the host body, it can be reattached by any effect that can typically reattach limbs or organs, such as the regenerate spell. A grafter can remove a grant using the same process required to implant one, though this does not necessarily restore any organs replaced by the graft initially. Grafts typically require specialized storage conditions, such as alchemical tanks, to remain viable outside of a host. Grafts can usually be upgraded into their greater versions by having a grafter apply additional surgeries, mutagenic development, or similar medical procedures.