Distort > Wave Warp effect
The Wave Warp effect produces the appearance of a wave traveling across an image. You can produce a variety of different wave shapes, including square, circular, and sine waves. The Wave Warp effect is automatically animated at a constant speed across the time range (without keyframes). To vary speeds, you need to set keyframes.
Original (left) and with variations of Wave Warp applied (center and right)
First example: Sine wave, small width and height second example: Semicircle wave, medium width and height
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