Sky Williams, 6'2" SG from Tuckahoe, NY apparently enrolled at WSU last fall and will be eligible this year. He's a friend of Early's.
Williams averaged 27.8 ppg in HS, led his team to a 25-0 record and a state championship in Class C, which appears to be a small HS classification in NY. He was on the 2013 U.S. Elite Basketball team.
He's in Florida working out with Cleanthony Early and Scottie Wilbekin right now.
Putting his HS stats together with his membership on a US Elite team, and working out with some studs this spring, it just doesn't add up that he paid his own way last year (somehow Manhattan is involced - he may have enrolled there or signed an LOI - that's not known), and will be a walkon this year.
This looks like the most mysterious and unusual walkon Marshall has had, and he's had some odd ones - including Malcolm Armstead, Ron Baker, and Lufile Coleby.