The odd thing about RA2 is that no matter how heavy your robot is, the lightest of flippers can flip it. Seriously, the standard Scout from DSL 2.1 can easily get under and flip Hammer of Judgment across the arena, even though it weighs several thousand kilos. The same thing could be with the fridge. It might be around 2000kg, but due to the weird physics even a lightweight can get underneath and flip it.