I don’t really have a name for these, I generally call them ‘bichos’ (which is a generic term is Spanish for bugs or insects). What makes them really effective is their big googly eyes, when they look at you, you think they’re real. You can buy the eyes with the finger piece from the shop Tiger and the other eyes you can buy from craft shops or you can order in bulk cheaply from China via Ebay, but they take a long time to arrive. Think about actions that they can do and your class will happily shout "Jump" or "Walk", "Sleep" to see what they do. Remember that they are more effective when walking around on something, such as up your sleeve or (as in the photo below) on your hand.