So my kids are obsessed with Invader Zim, especially Gir! I LOVE it too actually! Anyway, one son asked for the robot version for his b'day, the other asked for the dog suit version. Both turned out way better than anticipated. I believe you can find the pattern on Ravelry and the pattern is by Patty Rau. I know it is a free pattern, just can't remember exactly where I got it . I still need to get a pic of the robot alone, but he sleeps with my son EVERY night, so it is hard to get one! :)
Anyway, here they are:
I had to modify the pattern a bit, I made 4 ears instead of 2 and sewed 2 together to form each separate ear. It made the ears stand up better and keep their shape.