Valentine Surprise

SPOILER ALERT
On our way out of Town Park in Mansfield, my youngest was looking for places he thought would be good hiding spots.  He found a great tree, and happened to notice a letterbox that we didn't have a clue for!  It was a box called Valentine.  Inside it was a hitchhiker and a parasite-my first parasite!  We stamped in, and collected the hitchhiker and parasite to take with us before leaving the park.

Here are the 3 stamps and logbooks:

When I got home, I discovered that Valentine was a mystery box, and so I had overlooked it when searching for Mansfield boxes.  The parasite was called The Purple Parasite, and the hitchhiker was called Nancy Drew and the Mystery Letterbox Hitchhiker.