Pike killer Achievement
Destroy a pike*MISSABLE*
About two thirds of the way through the game, you'll come to a level where you travel by boat on water, having to jump off at various points to use dynamite to clear the water for the boat to continue on. Throughout this level, there will be a pike in the water that will jump up and try to eat you. To unlock this achievement, you need to take some dynamite down low enough (onto your boat works) and place it, then when the pike comes to eat you, hope that it blows up on time to destroy the pike.
This achievement is a bit of a pain because of the timing and luck involved. Sometimes the pike will just swim past and not jump up at you. So you will likely end up bringing dynamite to your boat over and over, trying to set it at the correct spot at the exact right time such that the pike jumps toward you and runs into the dynamite right as it is exploding. It's definitely going to take some trial and error, but stick with it and eventually you'll be able to destroy a pike. It's fine if you die in the process, as long as the game registers that the pike died too.
This achievement was also quite delayed for me, so if you're sure you did it, give it a minute to see if it unlocks.