Using Minecraft Classic Texture Pack Copper Golem is missing

I was using Copper Golem, and when I exited the world and launched the Minecraft Ciassic skin pack, the Copper Golem was gone when I re-entered the world. Without the Minecraft Ciassic skin pack, the Copper Golem was still there, but when I launched the Minecraft Ciassic texture pack, the Copper Golem was gone.