In the books
Hiccup encounters a Giant Bee-Eater on the island of Berserk, in How to Break a Dragon's Heart. The giant bee-eater roams through the forest with it's head over the tree line. Its mouth is wide open (about the size of a bathtub) while it drifts through the forest rather like a whale or basking shark. Hiccup and the Windwalker almost flew right into its mouth, swerving out of the way at the last minute. Despite mainly eating bees, their bodies do not have any problem digesting other distracted animals that find their way into it's mouth.
In the film
It is seen in the movie adaptation of How To Train Your Dragon when Hiccup is reading a book about dragon species. It looks like a cross between a Gronckle and a Terrible Terror, having thick legs, a rounded tail, and a long neck, complemented by fast beating wings similar to the Gronckle's.