There is **no "Slipper Paddle"** in Wii Sports Resort. You may be confusing:
| Sport | Unlock | Condition |
|---|---|---|
| Table Tennis | High-Grade Paddle | Beat Champion (Lucía) |
| Swordplay (Duel) | Master Sword | Beat Champion (Morgan) |
| Archery | Pro Bow | Beat Champion (Miyu) |
| Basketball | Pro Ball | Beat Champion (Takashi) |
| Frisbee Dog | Slipper Disc | Expert Difficulty |
If you saw a "slipper paddle" in a video, it's likely a mod or misidentified Slipper Disc (Frisbee).