  In the present work we explore the concept of solitary wave billiards. I.e.,
instead of a point particle, we examine a solitary wave in an enclosed region
and explore its collision with the boundaries and the resulting trajectories in
cases which for particle billiards are known to be integrable and for cases
that are known to be chaotic. A principal conclusion is that solitary wave
billiards are generically found to be chaotic even in cases where the classical
particle billiards are integrable. However, the degree of resulting chaoticity
depends on the particle speed and on the properties of the potential.
Furthermore, the nature of the scattering of the deformable solitary wave
particle is elucidated on the basis of a negative Goos-H\"anchen effect which,
in addition to a trajectory shift, also results in an effective shrinkage of
the billiard domain.
