Ex-UCF star football player Otis Anderson Jr. was allegedly shot and killed by his dad on Monday night ... after the two had gotten into an argument over a dog bite.
It's all spelled out in new police documents, obtained by TMZ Sports, in which cops say Otis Jr.'s mom, Denise Anderson, told them the whole, violent altercation started after her son's girlfriend's dog had bitten Otis Anderson Sr.
Cops say Denise told them Otis Sr. was so enraged over the bloody wound caused by the dog -- he and Otis Jr.