Can someone tell me what this is?

[Overlordraz]

Um wtf is this

 

[dwappo]

I'd like to know what modpack you're on, but... Where are you?

 

[Overlordraz]

... rily did you even look at the top of the picture i'm on the direwolf20 1.5 and im just out in the wilderness

 

[eric167]

texture fail.

 

[dwappo]

XD I'm on my phone lol. Didn't see the top.

Also, texture fail? What textures?

 

[Dex Luther]

Looks like raindrop fail. If you turn off the rain, does it go away?

It could be file corruption. Might want to try clearing that instance of the pack and downloading it again.
You could also try updating your Java or removing it completely and installing the most up-to-date version.

If that doesn't work, it could be something acting wonky with your graphics card. I've seen weird things happen just because a cable was loose or broken and the wires inside were frayed. Could also be your video card getting old or overheating.

 

[draeath]

They look kind of like the models used for one of the Twilight Forest mobs... but with an (obviously) corrupted texture.

 

[SpitefulFox]

They're Phantom Knights from Twilight Forest. They're from the Lost Hall of the Knights dungeons, but they're still WIP. They shouldn't be spawning like that unless someone is goofing around with spawn eggs.