Alex immediately searched around for whatever was generating the sonar, but failed to locate anything. The source seemed to be outside the range of his sense, so he'd continue to wait. Turning his attention to the reactions of the crab, he noted that he wasn't the only one who could hear the sonar, as the crab promptly responded by trying to frantically bury itself in the sand.
The sight of the giant crab burying itself in the sand was almost comical, throwing sand up into the water like a dog, as it tried to create a hole to bury itself. The problem was that this signaled something clear to Alex - whatever the source of the sonar was, the crab was terrified of it.
The crab had half finished burying it before the source of the sonar appeared in the form of a pair of orcas, shooting through the water as if fired from an arrow. They were pretty much indistinguishable from the creatures in his memory, at least in appearance. Powerful tails propelled them through the water, with fins to guide them.
The difference was that these creatures were now infused with mana, and they were pretty smart to begin with.
The pair of orcas quickly circled the crab, seemingly trying to decide how to deal with it. Soon, one rushed in, twisting its body and telegraphing a hit to the crab's shell with its tail. As it did so, the crab seemed to ready its one free claw, seemingly trying to strike at the orca's tail as it came into range.
Watching the strike descend, the orca suddenly pulled back its tail, changing its momentum, and feinting out an attack from the crab, who's claw clamped down on an empty ocean. The other orca then swooped in, closing its jaws on the arm of the crab, pulling it out of the sand and hurling it up toward the surface of the water.
'I guess they can't break its shell with their jaws?'
Alex expected the orcas to then attack the exposed soft underbelly of the crab, but he witnessed a completely different behaviour. Instead, coordinated another series of attacks, intermixing feints with real attacks, leaving the crab completely lost - they weren't particularly known for their intelligence.
As this occurred, they continued pushing the crab closer and closer to the surface, and managed to flip it upside down. The crabs seemed particularly vulnerable from the other side of their shell, their legs not proving particularly useful, and they didn't seem to have the mobility to reach around with their claws. The orcas exploited this, slamming the creature's carapace repeatedly with strike after strike, leaving it stunned.
They then coordinated a new strange maneuver, in which one swam below the creature, releasing a torrent of bubbles, while the other one shot at the surface with a huge amount of momentum, leaping into the air. The orca in the air then proceeded to land tail first on the crab, immediately crushing its soft underbelly, and sending it shooting towards the bottom of the ocean, where it proceeded to twitch.
As it lay on the ground, the orcas seemed to watch it apprehensively, not wanting to get particularly close to the writhing limbs. Alex watched the spiky limbs as they spasmed and agreed with their decision, he wouldn't approach as things were either.
Eventually the crab seemed to stay dead, and the orcas descended, beginning to dismember it with their jaws, before tearing into its soft underbelly.
In its daze, the two orcas approached, each grabbing a hold of a claw, before grinding through the joints with their teeth, severing the limbs. They then slowly started devouring the crabs innards, leaving Alex to watch in horror.
Horror, partly because of the devastating scene he'd just witnessed, and partly because he could feel hypoxia setting in. He needed to get to the surface immediately. Cursing silently, he unburied himself, before throwing himself towards the surface, stealth completely abandoned.
He had no hope of going unnoticed, so what good would stealth do him? Bursting through the surface, he exhaled deeply, recovering his oxygen. He then turned his sense towards the orcas, who definitely seemed to have noticed him, letting out a few clicks, presumably scanning him with echolocation.
Alex glanced towards shore - the closest point was around 800m away.
'Shittttt.'
He shot himself along the surface of the water in a desperate front crawl, eating away at the distance, propelling himself with his ability. His efforts proved almost entirely meaningless however, as before he could close even 100m to shore, the pair of orcas had almost entirely closed the distance.
Drawing his spear, he whirled, readying himself against the attack he could sense was coming. Watching the orca contort its body as it tried to get away from his spear, grazing past its eye, and skinning part of its cheek. The orca let out a few pained clicks, registering the bleeding in the water.
He then shot himself back a ways and thrust his spear again, skimming the creature's skin again - they were simply far too fast and evasive. He then noted the positioning of the second orca as it approached him from behind, jaws open. Grabbing hold of the mass of water beneath the orca, he heaved upwards, throwing himself down at the same time, causing its jaws to snap closed on the water.
In this time, the other orca had twisted in for another charge, and Alex had to fend it off with his spear. Again, he only managed to score a cut across the creature's skin, as it dodged out of the way.
Both orcas then promptly backed away, continuing to circle him, seeming to plan out their next attack. Alex used this opportunity to take another breath, and continue moving further to shore - only 600m to go.
This time one orca approached him, while the other swam below him and started generating air bubbles, filling the water with disturbances. This behaviour was somewhat nerve racking, as he couldn't figure out its intent, ignoring it, he chose to focus on the fight with the creature in front of him.
Again, it charged head first at Alex, trying to tear him apart with his jaws. He again countered with a spear thrust, but the orca seemed to anticipate this behaviour, its jaws starting to close on the spear. Putting everything he had into his water control, he accelerated the spear back while he yanked, barely getting it out of range of the orca's teeth as they snapped closed.
He and the orca continued exchanging a series of attacks and feints, though the orca seemed to be growing increasingly apprehensive and non-committal. Alex also noted that his spear was doing little to pierce the creatures thick skin and flesh, the few wounds he'd managed to create already healing.
The orca then went in for a bite which proved to be a feint, before turning and trying to slam its tail into Alex. Fortunately, he'd anticipated this, and managed to land a blow on the creature's tail, creating a small wound.
It then backed off, leaving him surrounded by a small field of air bubbles, and a strange sense of unease. Probing the air bubbles, he noticed that many of them were coated with a layer of mana. On further inspection, these air bubbles seemed to actually be filled with water vapor.
'Cavitation bubbles?'
The reality of the situation immediately struck him. They'd mixed air bubbles, with bubbles of steam generated through what he could only assume was cavitation - reducing the pressure enough that the water vaporized. They'd then somehow contained these bubbles using mana, and he was now surrounded by them.
If they collapsed while surrounding him, the pressure waves would crush his organs, turning him into jelly - he was basically in an underwater minefield. The other orca he'd been fighting had put 30 meters between itself and the bubblefield and it didn't look to be slowing down.
He had about 5 meters of water between him and the surface, and he needed to close that distance before the bubbles collapsed. He immediately pushed on the water surrounding him, accelerating himself upwards towards the surface, breaking through it just as he felt the water ripple letting out a fierce shockwave.
As he was airborne, little of the shockwave hit him, and he flew through the air, being given a brief reprieve from the combat. Glancing at the shoreline 600 meters away, he decided to burn his mana, pushing off the surface of the water, and shooting towards the shoreline flying through the air. He'd been trying to avoid using this method as it was extremely expensive, and he wasn't confident he could make it to shore, but he no longer felt he had a choice.
The orcas weren't going to let him escape that easily, and he could feel them closing the distance, seemingly having forgotten about their crab dinner entirely. As he fell towards the water, he felt one breach, snapping at him with his jaws, trying to catch him out of the air. Having seen the attack coming, he actually used the opportunity to push off the orca with his spear, hitting its forehead with the butt of his spear, further throwing himself towards the shoreline.
At the same time, he pushed against the water again, launching himself even faster towards the shoreline - he needed to put distance between himself and the orcas before his mana ran out. He felt his mana bottom out just as he reached the 50 meter mark, rudely depositing him in the shallows. Hooking his spear over his shoulder, he frantically began a front crawl, closing the distance on the shoreline.
As he crawled out of the water, onto the shore, he noted the two orcas fast approaching, not particularly seeming to slow down.
'Don't you dare.'
One of the orcas seemed to accelerate more, shooting out of the ocean towards him, trying to beach itself to catch him. Dropping into a roll, he desperately avoided its jaws, before turning and running, putting as much distance between himself and the ocean as he could - there was still one more orca.
After reaching a distance of 25 meters away he turned and watched as the beached orca wiggled its way back into the ocean, before departing with its partner.
'What a bunch of assholes.'