There is a good reason why restaurants and food manufacturers are catering to millennial consumers: They’re a massive generational force with an equally tremendous capacity for spending money.

Millennials started coming into adulthood around the year 2000 and are the biggest generation in U.S. and world history. Following on the heels of Gen Xers, or the so-called slacker generation, millennials are a group on the move, expected to spend as much as $200 billion annually by 2017 and as much as $10 trillion over their lifetime — and that’s just in the U.S.!

So what millennials want, restaurants and food companies are smart to give to them. But with that demand comes some odd preferences. QSR Magazine pegged millennial food habits as including a desire for diverse, unusual, customized fare that touts health as well as social consciousness. The following four food trends could be the next huge opportunity, even if some of them seem really weird.