Invasion of the Body Squeezers: Part 2 (Goosebumps 2000 #5) by R.L. Stine - Vintage Paperback

The alien opened its mouth revealing four tusks and rows of pointed teeth. A cap of green skin formed over its forehead, carved and hard like a turtle shell.

It spread its arm. Raised them out at its sides. And took a heavy, wet step towards me.

I finally forced my legs to move. I stumbled back.

"Are—are you friendly?" I choked out in a tiny voice.