It has long been noted that when two or more Reuniclus join hands, their thoughts join together and their power is dramatically amplified. Under modern rules which ban multiple pokemon of a single species from being teammates, and in an age when two wild Reuniclus is a high number to encounter in a lifetime, this sight is typically one relegated to the history books. But physical contact with a Reuniclus also has notable effects in a great many other species, although it does not nearly so mightily amplify their power.
When two other people or pokemon are linked by a Reuniclus' touch, their three brains merge together for a brief moment into a strange union of telepathy and perfect understanding. When the link is dissolved, the Reuniclus is unaffected by the mind meld, but they function as a conduit for everything from memories to sensations of pain – and serves to determine who is left with which. The ramblings of madmen and horror stories aside, there is no evidence that a Reuniclus can use these powers without the consent of both parties, but this is not to say that those melded by a Reuniclus' hand tend to be happy with their decisions.
When pokemon trainers use their Reuniclus' power to win matches, it is typically in either triple battles or through pokeballs to manipulate the levels of damage the pokemon believe themselves to have taken. This process is controversial and at times dangerous; the other use of Reuniclus is dramatically moreso. For Reuniclus can not only transfer memories and knowledge of the dying (as is the custom of many in Unova who fear losing everything with death) but provide relief from the most awful of physical and mental maladies, provided the victim can persuade someone else to absorb their pain.