There’s a Secret Weapon in Gears of War 4 called the “Despicable You”. It’s an Easter Egg Weapon in the prologue that can be picked up on insane difficulty.
If you go any lower on the difficulty the door you need to enter closes way to fast and it is very hard to get the weapon.
Make your way through the beach and destroy the first turret gunner with a grenade. After activating the first door and restocking on ammo, you will get to a new area with 3 enemies. Take out the two on the right as fast as possible and sprint to the door on the right behind them.
This is where you find the freeze gun called “Despicable You”. This is an easter egg weapon referencing the movie “Despicable Me”. You won’t be able to carry this weapon along for too long but it is fun to use as long as it lasts.