Fear in a 2 year old

I am a preschool teacher. Presently I teach a class of just two's with their parent or caregiver in the classroom. One little boy who was perfectly fine in the class, became frightened by a "dinosaur egg" I had last week. Inside the egg were several baby dinos. The children loved it..However, this child became frightened.This happened last week. Today he cried soon after the class started and wanted to go home. His mother says that this happens often when they go places and that he remembers things from a year ago and refuses to go back to the place where he was frightened! She doesn't ever push it, but wants him to be o.k. here because she plans to send him to preschool here in the fall.
What to do? It feels part manipulation to the extent that 2 year olds manipulate. I also wonder if it some sort of threat response of separation... Also, his mother says that all week, he was worried about the "cat" in school, no amount of reassurance helped. He worried and talked about it all week. What to do to ease him back into some level of comfort?

[Kevin Kennedy, Ph.D.]

Such children, who have as their baseline a sensitivity to situations that evoke fear, are best dealt with in a calm and supportive way, in which they are helped to adjust to whatever is required (e.g., attendance at your program). Their fears should not drive parents to keep them from situations that are ultimately helpful for them.