Children's book where alien friend of boy is thawed out after being frozen by enemy

I am trying to recollect the name of a children's book that I read in the 1990s where a young boy had an alien friend. Somehow the alien (who I believe was named Eric) was frozen and eventually thawed. I remember a scene where the boy (who was actually another alien in disguise) nemesis of the alien hypnotized the alien's friend with his stare. Illustrations were in black and white. The cover showed the small alien popping out of the freezer while the boy and his friend stared in amazement. I remember the line "That slime (name of nemesis) froze me!" The alien was thawed using the body heat of the main character, if I remember correctly. Thank you in advance!