Does anyone where this mod is from ive been looking everywhere for it

[Dingus-_-]

[Dingus-_-]

I've been seeing people playing these multiplayer maps on zombies with all kinds of crazy stuff. For example its kinda hard to see but in the background you can see a apothicon I've also seen someone on tiktok playing nuketown with the apothicon flying around and it being a boss battle of some sorts. I've asked the streamers on tiktok that play these maps but they either ignore or don't say how they got it, its always "i got it from a friends" or they just say the name of the multiplayer map. If anybody knows anything about this please let me know.