This is the 3621st most frequent Spanish word.
metió
"Metió" means "put in" or "inserted."
Here, 'metió' is used to indicate that someone entered into something, in this case, the water.
Ella se metió al agua rápidamente para nadar.
She got into the water quickly to swim.
In this sentence, 'metió' signifies becoming involved or embroiled in a situation.
Él se metió en una situación complicada por no escuchar.
He got involved in a complicated situation for not listening.
Here, 'metió' represents the action of inserting something, in this case, the dog's head, into a certain place.