This is based on the film Monsters Inc.
Scary feet - lift foot off the floor, replace it then lift other foot off the floor etc as quickly as possible.
Bunk bed scare - on tip toes , arms up, fingers clawed roar loudly. Then bend knees and repear roar. Children must go from one to the other
(repeatedly) as quickly as possible.
The kids awake - children lie down and be still and silent
Moster walk - take big strides, growling and waving arms.
Monster run - run as quickly as possible, waving arms and hissing loudly.
Explain each part of warm up to the children then pick different sections calling and changing them as necessary.
For safetly issues make sure children all run the same way.