Wunderschrotflinte

The Wunderschotflinte (German: Wonder Shotgun) is a Wonder Weapon that first appeared in Eiswüste. It is an extremely powerful semi-automatic shotgun.

Effectiveness
In terms of how powerful it is as regular-like gun (as in, it doesn't have extreme effects), it's probably the most damaging gun in the game. Its exceptional damage combined with it's high penetration makes it a very popular weapon. However, recoil is huge, and it's Rate of Fire isn't very good. Also, it's effective range is short.

Zerstörungschrotflinte
When Pack-a-Punched it becomes the Zerstörungschrotflinte (German: Destructive Shotgun). It gains a big damage boost, a faster reload, a larger clip, more ammo and even better penetration. It also gains a randomized Red Dot Sight.

Ausgezeichneteschrotflinte
When Super Punched it becomes the Ausgezeichneteschrotflinte (German: Excellent Shotgun). It gains another immense damage boost, along with a better range, less recoil and it also gains more ammo.

Trivia

 * The image of the Wunderschotflinte is the Type-52 Pistol (or Mauler) from Halo 3.