Wind-up frog toy
From Create Your Own Story
"Alright, Koromon!" you shout. "That frog is your opponent! Attack it with your Acid Bubbles!"
"Alright!" Koromon yells with confidence. It leaps over to the frog toy, takes in a breath and puffs out a stream of acidic bubbles from its mouth. "Acid Bubbles!"
The attack was a direct hit, leaving the toy's body slightly eroded away. The melted parts of its arms and legs flows to the floor while small trails of smoke rises into the air. You gaze at Koromon's handiwork, being quite amazed at its power. "Great job, Koromon!"
As Koromon turns around and smile at you, your smile disappears when the frog toy behind it suddenly grows in size as a white light embraces its body. When the light fades, a Betamon-like Digimon stands in its place. It looks like a Betamon, but it has two additional fins on its head. Moreover, it looks angry, unlike the usual calm and peaceful Betamon.
"Koromon! Behind you!"
The moment you gave the warning is also the one when the 'Betamon' spins itself in Koromon's direction, rapidly pelting its pinkish body with its fins. You need to do something quick!