Salesforce CEO Marc Benioff pulls a funny trick to get his cofounder to wear a crazy costume

The conference is extravagant in every way possible, from last year's cruise hotel to Stevie Wonder's opening concert - and it completely shuts down parts of the city during the week-long event.

But to some people, the best part about Dreamforce is getting to see Salesforce's lesser-known cofounder Parker Harris dressed in a funny costume during his keynote speech.

Because in recent years, Harris has been showing up in crazy costumes ranging from a superhero called "Lightning Man" to a scientist resembling Dr. Emmett Brown from "Back to the Future."

But for some reason, Harris doesn't seem to be in the mood for a costume at this year's Dreamforce, says CEO Marc Benioff. So he's asking his 260,000 Twitter followers to convince Harris to do it again this year - by sending him a personal email.

Einstein is the name of the next big product Salesforce is rolling out at this year's Dreamforce. Not much is known about Einstein, but it's supposed to be a product that uses artificial intelligence to make the software "smarter."

Judging by the responses next to Benioff's tweet, a lot of people are pushing for Harris to dress as Einstein.

And to give you a clue to Harris's past costumes, here's a look at his last three keynotes: