Dump instant pudding into a large mixing bowl. Add pineapple with juice; mix well. Stir in whipped topping until combined.
Add bananas, marshmallows, fruit cocktail, and mandarin oranges; mix until incorporated.
Cover and refrigerate until thoroughly chilled.
Tip:
IF YOU DON'T WANT THE BANANAS TO TURN BROWN SOAK THEM IN THE PINEAPPLE JUICE AND ADD A SPLASH OF LEMON JUICE WHILE YOU PREPARE THE DISH. I promise they will not turn brown.