Board Thread:Theories and Speculation/@comment-2165692-20170426120148/@comment-25122992-20170426182013

Besides, people, I think there's no reason to speculate about the appearance of the creature, since OnlineLurker pointed out once it that it looks like a Nue, so it's not a gorilla whatsoever. Also, the only part of it that took action was its sneak-headed tail, which means that wasn't an actual snake.

Regarding the summoning process itself, yeah, it clearly didn't look like a usual one. I'd also say that the creature somehow managed to tamper with Boruto's summoning, and instead of summoning the usual animal he signed a contract with earlies, he summoned the creature itself.