Sphere 3D Corp. (ANY)

[blueblizzy]

It happens when no one is willing to pay for shares above a threshold price, but will gladly pay for any shares made available below the threshold price.

Sometimes manipulation is involved when that same person puts in one or more large ask orders in with the intention of keeping a lid on upward price movement (shows up as a huge ask wall on the Level 2). That same person would have a bunch of bid orders in to scoop up cheaper shares.