Arrange a layer of ice cream sandwiches in an 8-inch square dish, trimming as needed to fit.
Warm hot fudge briefly so it spreads easily, then spread part of it over the sandwich layer.
Drizzle caramel topping over the fudge.
Add another layer of ice cream sandwiches.
Spread remaining hot fudge and caramel over the top.
Cover with thawed Cool Whip.
Sprinkle with toffee bits.
Cover and freeze until firm, at least 4 hours.
Slice with a warm knife and serve frozen.
Notes
Let Cool Whip thaw fully so it spreads smoothly. Warm your knife under hot water and wipe dry before cutting clean slices. Keep covered in the freezer up to 5 days for best texture. Double the ingredients for a 9x13 pan.