Looks like the SLAPAYO glitch from VBrawl https://www.ssbwiki.com/SLAPAYO
The glitch itself seems to be very rare usually involving Ness being hit while charging but not necessarily needing to have clanked with the Yoyo hitbox. Last time it has been documented was by 2 random kids 5 months ago...
DK received no changes this patch. Pichu on the other hand was nerfed losing some of his stronger options (CHUU Spam being the main one) and had a few moves weakened.
So I am currently making my own hack pack for me and some friends of mine and would like to change the hitstun. I would like to know how much hitstun is in minus so that I can change the hitstun in my hack to be similar to minus as I find minus's hitstun to fit well with the idea of my mod pack.
Once upon a time I had another account here. I forgot the password and username and it was on an old email so now I have this account. Anyway here are a ton of replays with MetaKnight.