Solar tsunami has been imaged...

by NASA's STEREO (Solar Terrestrial Relations Observatory) spacecraft, and consists of a wave of hot plasma and magnetism that races across the Sun's surface, generated by a coronal mass ejection. The scale is humongous:

"The technical name is "fast-mode magnetohydrodynamical wave"—or "MHD wave" for short. The one STEREO saw reared up about 100,000 km high, and raced outward at 250 km/s (560,000 mph)."

Fortunately the phenomenon is no hazard for Earth.