wierd Minecraft glitch thing

ok. so I was derping around on the server and all of a sudden I look over and see this. I have no explanation. all I know is that I had some one else come look and they couldn't see it and I reclogged and it went away. I just want to know if this has ever happened to anyone else or if some one can explain it.

It has never happened to me.  But I never use any texture packs or mods.  I think it has something to do with the texture pack you are using.  Maybe you can fix it with mcpatcher???? (I am assuming that you are talking about the red x on the blocks.....right??)

Yes im talking about the red X. and I was using a texture pack but it was still there after I turned it off >.>

X Marks the spot, so you clearly have to dig them!

But seriously, I have never seen this happen. Do you have any mods installed? That is the only thing that I think could cause this...

Maybe you should turn off all those h4x.

No but srsly.. was it still there if you switched back to default?

yes i had mods installed. >.> don't remember all of them. but it was the same with default until I relogged

Those redx's are from a mod that allows you to see the brightness level of each individual block.

TheChopper is right, hit F7 to get rid of them. The red x's show areas that are dark enough that mobs can spawn it. This is a part of one of your mods  most likely, its in FTB. Pretty handy when torching an area :)