Instos (the big players, also known as institutions) regularly engage in market tinkering. This is largely designed to "trick" retail investors, which are the people who trade from work or home (like you and I). One of their common tricks is to pad out the buy or sell side of the market with very small orders. This has two key effects. First, it gives the outward (superficial) appearance of greater buying or selling interest than might otherwise be the case. Second, it can cause the SP to behave in silly ways, and those movements can entice reactions from retail investors, which the instos then pounce on for their own advantage.
For example, let's say an insto pads out the buy side with a bunch of high bids for only 1 or 2 shares each. Then, they can trade into those bids and drive the price up without really spending much to do so. Retail investors see the price spike and will often buy in because of FOMO, which the insto can then use to sell back down into.
This is just one example, and I'm sure others know a lot more and can explain better, but hopefully this sheds some light on it
ISX Price at posting:
84.5¢ Sentiment: Buy Disclosure: Held