Certainly not a high priority idea, but I was thinking today about a few potentially amusing 'Scampers' megabeast concepts.
Essentially, instead of being a single form of Megabeast, Scampers would take the form of at least three potential megabeasts that would appear to the player exactly the same, but would have a variety of behaviors to display. Essentially, whenever 'Scampers' arrived on the map, it would act as if any Megabeast showed up. The player would have no idea which form of Scampers had arrived until it displayed the behavior associated with that form. As I said, I can think of three :
Bad Scampers! - This is what you'd expect of a Megabeast. An evil beast of doom and death. While perhaps not particularly as strong as any other Megabeast, it would be incredibly fast - thus getting in hits more often and moving with insanity. This is pretty straightforward.
Sweet Scampers - This version of Scampers would act like a super kitten to all dwarves for a period of time before wandering away from the fortress. Scampers would appear, run around your fort, chase down vermin (and possibly goblin/kobolds/treehuggers elf bastards who attack, including ambushers), and bring them to dwarves, while also generating happy thoughts for any dwarf Scampers happens to run across. Basically a wonderfully good benefit for a month or year - whatever.
Sleepy Scampers - Lame name, I know, but this form of Scampers represents a very realistic cat. Essentially, Scampers would enter the Fortress, immediately search for the most used traffic area of the fortress, promptly go there, and sleep. For months. While asleep, Scampers is essentially a wall and impassable (lest you awaken instead the wrath of Bad Scampers!).
Probably more concepts, but I like the idea of a schizophrenic Scampers. Possibly other Scamper personalities as well could show up. Who knows. Have at it.