Rewrite a sentence to introduce a surprise element into the story.
Robbie went fishing with his dad.
To his astonishment, Robbie caught a gigantic fish while fishing with his dad.
Complete the following task based on the instruction and optional input provided.### Instruction:
Rewrite a sentence to introduce a surprise element into the story.

### Input:
Robbie went fishing with his dad.

### Output:
To his astonishment, Robbie caught a gigantic fish while fishing with his dad.