Universal Gravitation Device

The Universal Gravitation Device was an unseen item given to Yoshi by the spirit Hongo in Yoshi's Universal Gravitation, however considering that the player controls the gravity via Gameboy, it's possible it's appearance resembles one.

It allowed Yoshi to manipulate the gravity of levels; the player can turn them on their sides, roll or unroll things, etc. This allows Yoshi to access parts of levels that he wouldn't be able to normally, such as being able to climb up walls/ceilings by literally walking up them, or move objects by merely tilting them on their side and making it roll for example.