Well definitely Sparkster, I doubt anyone could dispute that. They screwed thousands of investors with false promises, delivering a product that a first year student in a tech/computer high school could throw together. All in all, a major clusterfuck that left a big black spot on some "established" crypto influencers as well.
I recall how the lots of Ian Balina hyped the project they looked promising but yet failed. One thing is certain, without past tract record these developers are bound to fail many ideas are I teresting on paper but can't be implemented.