It doesn't have to be obvious at once. Especially since it's both little and a shadow.
And it will make a great difference in their choices of actions, especially since they lock the portal after themselves to prevent following. On one hand, panic and desperate pursuit. On the other hand, trudging search for other people, which they would call desperate, but which is conducted on slower lines, if only to keep them from dropping of exhaustion, since they know it will take a while.
Hmmm. . . is the one that made it going to be frightened and limited in action, since it was expecting to be able to drag along a lot of friends? But it is going to have great impact on their ability to appeal for help, which they need, since they are under a curse. . . .