I did/do not see an overt similarity to the Sleipnir, other than the play on the name. I much prefer the shape of the Slapnir.
I think “wrecking ball” would be a great name for an unapologetically heavy yoyo (credit to @Benthrowsyoyo - Yoyo materials OF THE FUTURE - #15 by Benthrowsyoyo)