Equipment:
Balloon or large ball (soft or hard) for each person. Small tennis size balls might work depending on how comfortable players are in being cosy/close to the other players. If using balloons have a few spare for any that burst.
Play
Break the group into teams as this is a relay style race. Designate a starting point and an obstacle (or obstacles) that each team has to run/walk around. Each person in the team gets a balloon or ball or whatever you are using.
The first person in each team holds the balloon/ball in front of them against their bellies (tummy/stomachs) and runs around the obstacle/s back to their team. Where the next person in the team joins behind them, but have to hold and keep their ball/balloon between the back of the person in front and their own tummy/stomach ‘without’ holding the ball with their hands (putting their hands on shoulders of the person in front). They now both go around the obstacles, returning to add the next player and so on building up the caterpillar until the last team member has joined the caterpillar and the whole team gone around the obstacle/s.
If a team member drops their ball/balloon or a balloon bursts the team goes back to the start line and starts again with the number of players that were already in the caterpillar.