Magical Arm Shield (SBC1-ENI22) [Speed Duel: Streets of Battle City]

When an opponent's monster declares an attack while they control 2 or more face-up monsters and you control a monster: Target 1 face-up monster your opponent controls, except the attacking monster; take control of that face-up monster (until the end of the Battle Phase), and if you do, change the attack target to it and perform damage calculation.