A hostile takeover occurs when one company looks to acquire another "target" company whether or not the target company desires to be bought out. The acquiring company does this by buying up a controlling amount of the target company's stock shares. In order for this to happen, the target company must be a public company and a large number of its shares must be readily available for purchase on the open market.
Most of the time one company wishes to purchase another company, even forcibly, because of the target company's profitability. This means that the acquiring company will keep the target company doing the same thing it was doing before it was acquired, except now it will be under new ownership and therefore someone else will be reaping the rewards of the company.
An alternative option is the acquiring company conducts what is commonly referred to as a "corporate raid." What this means is that the acquiring company looks to forcibly buy up a company who has a low stock price because it is not doing well, but has valuable tangible assets such as equipment or land. After the acquiring company has successfully conducted the hostile takeover of the target company, it liquidates the company by selling of all of its equipment and land, effectively destroying the target company.
