In a dark corner of a London playground the crowd is baying for blood. Two young fighters are limbering up for their first combat. These are no ordinary schoolboys preparing for a fight - they are DigiMons, virtual monsters, the latest brainchild from the makers of Tamagotchi virtual pets.
Described by their Japanese manufacturer, Bandai, as the "ultimate modern-day conkers", thousands of these matchbox sized beasts, launched last week in the capital, have made their way into the hands of children. Thousands more are expected to be sold across the country in the weeks to come.
Lock one monster to another, switch them into battle mode and the fight begins.
Without any more help from their human owners the creatures, which develop their own characters according to how their young owners treat them, then battle away.
Excited bleeping noises emanate from the DigiMons as combat begins and punches are immediately fired across the electronic contact. DigiMons will fight to the death and a skull appears on the screen when one is ultimately defeated.
To ensure a DigiMon is victorious, it has to be constantly fed and watered and its droppings must be cleaned up. They can be built up with protein diets and training or made puny through neglect. They are trained to fight daily by boxing practice with their shadow.
According to Bandai, DigiMons, which cost Pounds 10 each, thrive in an atmosphere that is sweaty, dank and filled with loud music.
Young people are thrilled with the toy which adds another dimension to the virtual pet. However, the child protection group, Kidscape, is concerned that the new trend will lead to an increase in violence among young people.
A spokeswoman said: "This toy is a bully's delight. It is encouraging children to fight individually as they actually need to go out and find someone to fight with.
"We don't need any more violent toys which teach children how to fight. We need toys which teach children co-operation and how to play together."