As a child, the monster manual was a big thing and D&D a big part of my life :D
I stumble upon my old book and have to do one monster.
So the cockatrice : a chicken like monster with a lizard tail, bat wings and a paralysing bite !
I dislike the batwings, but chicken wing with no feathers looks quite pleasingly and close enough !

I'va added some of the intermediate sketches for the courious ones :D
C&C welcome.