Flying Flashing Endermen

I was on the hunt for endermen at night just jumpin around like normal when I found one near my house. I went for it (I am pretty sure I didn't look at it but it is a possibility I was really far away though) and it teleported away I couldn't find it so I kept on jumpin around. Then I saw it again but it was teleporting all across the map and flashing red as if something was hurting it. It wouldn't stop and I noticed other endermen doing the same thing. I couldn't find anything online so I thought I'd let you guys know. I've never seen this before 1.4.2