Jayson Tatum goes behind the back and hits the and-1 lay in traffic

Can someone enlighten me on what Jayson Tatum was trying to do here

Jordan Bell with the block, Steph Curry hits the 3 on the other end

Devin Vassell hits the one-legged 3 pointer to beat the shot clock

Ja Morant Floater Too Smooth Even for Wemby to Block