The Ice-cream men

 General: 

The Ice-cream men are a group of unknown origin. They are classified as cryptids but nothing is known about their physical description. The name was created quite bluntly from their appearance and methods.

The Ice-cream men have never been seen. Their effects are traced to the jingle of an ice-cream truck late at night; when no child would ever be buying ice cream. The jingle is never accompanied by the van. The van is never seen. For all of human history, the ice-cream men are believed to have operated on the outskirts of society. Their jingle is always accompanied by a disappearance.

Classification:

The Ice-cream men have only recently been categorized as an actual cryptid, as one incident involving a child became news-worthy. The child had reported seeing the van and hearing the jingle late one night. She is believed to be the only surviving person to observe the ice-cream men and we have no understanding of their general motives or why they didn't take her like they do the others.

Efforts to detain:

There are currently no efforts to contain the ice-cream men. They are never seen, never stay in one place and never leave witnesses. No current ideas for even locating the ice-cream men have ever been successful.