"Blue-Eyes White Dragon" attacks "Hayabusa Knight", but Joey activates "Nutrient Z", increasing his Life Points by 4000 before Battle Damage is calculated (Joey 100 → 4100). The attack continues, destroying "Hayabusa Knight" (Joey 4100 → 2100).
Sets a card.
Joey Wheeler's Turn
Joey draws "Time Wizard" and subsequently Normal Summons it (500/400) in Attack Position.
Activates "Time Wizard's" effect. Joey's luck roll is successful, so he can transform "Baby Dragon" into "Thousand Dragon" (2400/2000). (NOTE: in the real game, "Time Wizard's" special ability is slightly different and actually uses "Baby Dragon" to give rise to "Thousand Dragon" through Fusion Summon)(NOTE: If Battle City rules were to permit a Fusion Monster to attack the turn it was summoned, Joey would have been able to attack directly and won, as Seto only had 700 Life Points remaining).