  Activation functions are crucial in deep learning models since they introduce
non-linearity into the networks, allowing them to learn from errors and make
adjustments, which is essential for learning complex patterns. The essential
purpose of activation functions is to transform unprocessed input signals into
significant output activations, promoting information transmission throughout
the neural network. In this study, we propose a new activation function called
Sqish, which is a non-monotonic and smooth function and an alternative to
existing ones. We showed its superiority in classification, object detection,
segmentation tasks, and adversarial robustness experiments. We got an 8.21%
improvement over ReLU on the CIFAR100 dataset with the ShuffleNet V2 model in
the FGSM adversarial attack. We also got a 5.87% improvement over ReLU on image
classification on the CIFAR100 dataset with the ShuffleNet V2 model.
