F*** Yeah Seaking is a photoshop meme that superimposes an exploitable cutout of Seaking, a water-type fish Pokémon character, in images depicting various natural disasters and scenes of horror. While it has been often criticized as a largely forced meme on the imageboard site 4chan, it eventually gained a solid fanbase and spawned a number of rhyming derivatives in similar fashion to Haters Gonna Hate.
Definition of a Forced Meme:
A forced meme can be commonly defined as something that a person or group attempts to force into internet culture. Many forced memes never become embraced by the communities they are forced upon, but some have successfully become a part of Internet culture.
It's just something silly that was initiated by a bunch of people. Seaking is being used because of Horn Drill (I guess; that's how I interpret the meme), and that's a OHKO move if it hits. Seaking is usually depicted destroying things, like the Titantic.
Seaking is just a mediocre Pokemon, with a rather plain design (resembling a koi carp), that's been forced into a make-shift cool image.