Invasion Repelled

In what authorities have deemed the most blatant attack to date by the Delphinidae, known to live off the coast of South America. A small advance party was successfully repelled by alert beach-goers who acting swiftly and earnestly were able to turn them about and send them back to where they belonged. Stunning footage of this action can be found here. Their shouts of " Ei você, sair da praia!" not quite distinguishable above the sound of the crashing surf.

Contest to see if anyone still reads this blog.

What do these three pictures have in common?

Extra credit - What cartoonist inspired this challenge?

The winner gets to feel very witty for having figured it out, but other than feeling of smugness, there is no other prize.