Board Thread:Theories and Speculation/@comment-2165692-20170426120148/@comment-734582-20170428084545

Dragonoidzero wrote: if what ever boruto summoned is part of his power or it is part of the reason why people are getting possessed by the dark chakra. Considering Konohameru specifically calls out that Boruto shouldn't have been able to summon it, i think it's a dead giveaway that it's not his original power. It also seems to violate what we know about summoning (contractual and non-contractual).

Hence the Dark Chakra connection, which would in fact fulfill the requirements and works with what we know of Summoning.