How to identify if you have a Crazy Ant problem look at the video below, they have a very unique characteristics.
Rasberry Crazy Ant watch Them in action click on the video link
List of Common Characteristics to help determine if you have Rasberry crazy ants, provided by TAMU
If you see the appearance of many and the mean millions of uniformly-sized 1/8 inch long, reddish-brown ants in the landscape, grass
They will also forage indoors from outdoor nests.
These ants will form loose foraging trails as well as forage ( meaning in search of food) randomly (non-trailing) and crawl rapidly and erratically.
These Ant colonies are not built in centralized nests, neds or mounds, you will typically locate the queen and brrod under landscaping objects, like rocks, cross timbers, and piles of debris.
What exactly is the harm of the Crazy Ant?
Seems like mostly a nuisance and annoyance because of their sheer numbers. I cannot really imagine sitting outside with my pets and being swarmed by millions of these little crazy ants, but that is what has happened. They do not have stingers but can bite and the bite can be slightly painful.
Biting and medical implications to people, livestock and wildlife: Rasberry crazy ants do not have stingers. In place of a stinger, worker ants possess an acidopore on the end of the abdomen, which can excrete chemicals for defense or attack. They are capable of biting, and when bitten, they cause a relatively sharp pain that quickly fades.