Cannabis
Hashish (dried resin) is much more concentrated than cannabis (it includes both leaves and flowers).  Because of this, people who take large amounts of hashish may feel even stronger effects. They may also see things or hear things that do not exist (these are called hallucinations). They may also have strange thoughts. Some hashish users like the feeling of these visions and thoughts, while others may find them scary.  However, people rarely get hallucinations after smoking or eating cannabis.