Toddler has Black Stool

My now toddler just produced black stool today? No signs of constipation, lethargy, or sickness(paleness, passing out, blood in stool/mouth). He’s acting completely normal, happy and crazy as ever. This is the first time other than his newborn bowel movements that this has happened. I was told that if it happens again within the next day to take him to the ER.. but I’m a little concerned now. Also I am a FTM so if I do need to take him, do I also need to bring the poop?