Belch

You release a tremorous wave of air, capable of knocking a creature to the floor with sheer force. A creature within range that you can see must make a Strength saving throw or take 1d4 Thunder damage and be staggered. The next attack made against a creature staggered this way is made with advantage. The damage dice becomes d6s if there are any creatures currently Bellied by you.

The spell's damage increases by 1d4 (or 1d6) when you reach 5th level (2d4 or 2d6), 11th level (3d4 or 3d6) and 17th level (4d4 or 4d6).

This is a Vormancy spell, not Transmutation, part of the Dungeons and Dinners additional rules set on GM Binder.