Seattle Seahawks receiver Laviska Shenault Jr. didn't have much time to celebrate his 97-yard touchdown ... 'cause shortly after running the kickoff to the house, he got on one knee and puked his brains out!
The nasty moment went down during the third quarter of "Thursday Night Football" -- Seattle was trailing the San Francisco 49ers big ... but Shenault took matters into his own hands and scored off a kick return.
The highlight must have taken everything out of Shenault .