The phrase 梦幻泡影 (mènghuàn pàoyǐng, 'dream, illusion, bubble, shadow') comes from the Diamond Sutra (金刚经) and is used to describe the transient, illusory nature of all phenomena in Buddhist philosophy.
usage
In modern Chinese, 梦幻 is widely used as a trendy adjective meaning 'dreamy' or 'fantastical,' especially describing aesthetics, scenery, or experiences: 梦幻般的 (dreamlike), 梦幻色彩 (dreamy colors).