F*** YOU, KAI!!! TMZ.com
Kai Cenat said Kevin Hart's got the height of a leprechaun ... and TMZ Sports got an immediate response from the man himself -- with Hart telling Cenat to go "f*** himself!!"
We caught up with the comedian out on the streets of NYC shortly after Cenat hopped on "First Take" with Stephen A. Smith ... an appearance in which the ESPN talent compared Kai's athletic ability to Hart's.
The streamer did not take the notion too kindly .