Coextinction is when one species of plant or animal becomes extinct along with other species that rely on it for survival. It's like a big chain reaction, where if one species disappears, it can cause other species to disappear too. Imagine if your favorite toy was a plush teddy bear, and you needed it to fall asleep every night. If someone took your teddy bear away, you might have trouble sleeping, and you might even start to feel sad or anxious. Coextinction is like that, but on a much bigger scale, with animals and plants depending on each other for food, shelter, and other important things they need to survive. When one species disappears, it can have a big impact on the whole ecosystem, and other species might not be able to adapt quickly enough to survive without it.