The kuma is the kid that lingers around you when you're eating ice cream. He/She wants the ice cream for himself/herself. Could be a brother, sister or a complete stranger. Sometimes would make a fuss so that his/her mom would buy him/her one or, if not, ask you for him/her a piece of what you are eating.
As an adjective, kuma is how you'd describe that kid. Curious is too cute, greedy is extreme.
Here comes the kuma.
My child's seatmate in class is super kuma.
Also applies to adults.