| Clue | Source | Date |
|---|---|---|
| Bones and tennis balls, e.g | Universal | 13 Jun 2022 |
| Tennis balls and tug-of-war ropes, e.g | Wall Street Journal | 17 Aug 2021 |
| They're chewable but not meant to be eaten | New York Times | 30 Mar 2019 |
| They're chewable but not meant to be eaten | ||
| Rubber steaks, e.g. | ||
| Rubber bones, e.g. |