Are these supposed to be able to onto land? Because I saw one and puncher it and it started to flee and it got on land,I did kill it though? I'm a tell you the story so yall understand more

I live on herbivore island and oneday,my 3 pets,2 itchy and my basilo did odd noises,I can over and they were swimming around this thing,I punched it and it was terrifying,I thought it was going to attack but it just slowly moves away 😅🤔 It then swam onto land and I was like 😯 I used my entire pack of gigantosaurus' but they didnt attack it,so I finished it off myself the end (I have 10-20 gigas)