When the Time Stone becomes attached to Tony's arc reactor, it causes him to de-age and brings dangers from other eras, including dinosaurs, into present-day New York City.
When the Time Infinity Gem becomes attached to Tony Stark's arc reactor, it causes him to begin de-aging and brings dangers from other eras (like dinosaurs, futuristic robots and lost HYDRA squadrons) into present-day New York City. Things get worse when Red Skull is freed during the crisis and restored to his sanity.—Wikipedia