The incident happened Tuesday near Austin Street and Iowa Street, according to Mariah Schliesing.
The 16-year-old was in the passenger seat of her grandfather's truck as they spotted the monkey in the street.
"I wanted her to take a picture of it, but we never thought it would jump in the window," said Michael Schliesing, Mariah's grandfather.
Michael says moments after he rolled down her window, the monkey jumped into the cab.
"It hops onto the window of our truck and it does that thing that it does. I'm scared. It jumps on me," said Mariah.
She showed us scratches on her shoulder, neck and head which she says were caused by the monkey.
The attack only ceased when her grandfather hit the monkey.
"I hollered at it and I hit it right in the head right in the face and knocked it out the window," said Michael Schliesing.
Just like that, the monkey was gone. They don't know where it came from or where it went.
The monkey did not bite Mariah, so she didn't have to get a rabies shot. Her doctor did give her antibiotics for the scratches.
The city of South Houston's Humane Department is trying to locate the monkey.
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