A joke that originates on the Misskey community of ActivityPub servers, refers to a sex act involving two hedgehogs (like those from the Sonic The Hedgehog franchise) 69-ing.
Oh damn, look they're really going at it-- not everyone can pull off the sonicman69!
something said to individuals in one's approximate social group that look like they might have heritage from another group. It's kinda a jackass/perjorative thing to say.
"oh damn girl you mixed with something ain't ya?"
"I tell ya Janice that boy Courtney brought home looked like he mighta been... been... MIXED WITH SOMETHING!"