Struggling
Some creatures in Beasts of Bermuda possess very powerful jaws that can be used to grab prey. Some prey, however, is capable of escaping these jaws, at a significant cost to their own well being. To struggle free of another's jaws, a player must simply use their right mouse button while grabbed. This will set them free, at a cost.
Escaping a grab inflicts substantial damage and injury to oneself. It also is very exhausting, taking a very large fraction of a player's stamina and ability power. If a player is grabbed when they have insufficient stamina or ability power, they will be unable to escape the grab. If a player has low HP, they may end up struggle-killing themselves trying to escape.
Currently, the only creature capable of escaping a grab is the Ichthyovenator. It can do so, in combination with use of its dart ability to attempt escape of an aggressive Mosasaurus. It can only execute this grab if underwater, so an attacking Mosasaurus could potentially delay its prey's use of struggle by breaching with prey in its jaws, thrashing in midair.
Struggling was put into Beasts of Bermuda as a means to allow the Ichthyovenator a means to escape the Mosasaurus, who would otherwise kill the creature in one grab attack through the use of thrashing. It is highly likely some terrestrial animals will be able to struggle out of the jaws of a Tyrannosaurus rex in the future, as this animal is both planned for implementation, and is planned to possess a grab.