I totally get why a celeb would want to do an animated movie -- no hair and makeup! You can show up in your sweats and fifteen pounds over your fighting weight! You can wear your casual weave! But do people really want to see a movie about cavemen? Emma Stone, hold out for something a little more Toy Story and a little less The Flintstones.
First of all, this movie sounds bad. Per Wikipedia: "Surviving in a volcanic world is tough enough, but caveman Grug (Nicolas Cage) gets a rude awakening when an earthquake forces him to leave behind the only world he knows. With his family in tow, he ventures out into the volatile world in search of a new home. The situation becomes even more complicated when Grug's family — in particular his oldest daughter, Eep (Emma Stone) — falls for a nomad named Guy (Ryan Reynolds) they encounter on their dangerous journey."