If you want to go for the jugular and take no prisoners, The Web gets a more visceral reaction than any card effect you've performed! 

In fact, there are some people you simply should not do this effect for because while it starts out so innocently, you end with such a startling punch! 

This makes 'em jump up and scream! Four blank cards are counted onto the spectator's palm-up hand. Then pictures of spider webs appear and disappear from the faces of the cards. To conclude, the spectator is asked to wave his hands over the cards. As he does, he discovers a large, realistic spider on the back of his hand! At the right time, in the right place, this receives an unprecedented response-you will make people scream!