Fusion

You and another willing, corporeal, living creature of no more than one size larger or smaller than you fuse into one being. As the manifester, you control the actions of the fused being. However, you can give up this control to the other creature. Once you give up control, you cannot regain it unless the other creature relinquishes it.   The fused being has the total of your Hit Points and the other creature's Hit Points. The fused being knows all manifestations of both creatures, knows or has the prepared spells of both creatures, and has the combined total spell slots of both creatures. Any conditions present on either creature are present on the fused being, and all spent spell slots remain spent. Likewise, all feats, racial abilities, and class features are pooled (if both creatures have the same ability, the fused being only gains it once). For each of the six ability scores, the fused being's ability score is the higher of yours and the other creature's, its Hit Dice are those of both creatures combined, and the fused being has the higher level of the two creatures. The fused being gains all Proficiencies and Expertise of both beings.   You decide what equipment is absorbed into the fused being and what equipment remains available for use. These fused items are restored to their original owners once the manifestation ends. When the manifestation ends, the fused being separates with both creatures appearing in the nearest unoccupied spaces. If separation occurs in a space without room for both creatures, both creatures are shunted to the nearest unoccupied space, taking 12d6 Force damage, and are Stunned for 1 minute.   Damage taken by the fused being is discarded when the manifestation ends. Each constituent creature of the fusion is returned with exactly the same amount of Hit Points it had before it entered the fusion. However, any resources spent by the fused being are transferred to the original creatures when fusion ends. Any conditions or other effects are gained by both creatures when the fusion splits.   If a fused being is killed, it separates into its constituent creatures, both of which are also dead. You cannot use fusion on a being already fused by this manifestation.