Sometimes you have to make a sick play in poker to maintain your edge over the other players. If you become too predictable, or sprout a leak somewhere, other observent players will exploit you. This play is a great example of a play that doesnt have a lot of short term value - in fact its incredibly risky - but all great players have to be able to make situational based high risk plays in order to be un-exploitable over the long term. When your opponents fear you in No Limit Hold Em, you cant be exploited. When other players fear you, they wont bet into you without the nuts because you are liable to reraise them all in at the slightest hint of weakness.
What you see above is a rather extreme, high stakes version of the Sick Move. Playing $300/$600 No Limit Hold Em, David Williams makes it $1800 to go from early position. Brad Booth, sensing weakness, makes a raise to $5800. Phil Ivey looks down at KK and makes it $14,000. It gets back to Williams who folds, and Booth thinks for a while before calling. Phil has about $300K in front of him, and Booth has him covered. Booth's preflop call is correct because of to the implied odds he is getting on Phil's whole stack, which Gabe Kaplan notes in the commentary.
The flop comes all low cards, 3-6-7. Phil makes a standard bet of $23,000 into a $28,000 pot. And thats when things get a little bit crazy - because Brad Booth responds by putting 3 massive $100,000 bricks of cash into the pot! It looks like some crazy move on TV - and it is - but there is a method to the madness. The reality of deep stack poker is that only 5-6 hands can ever call in that spot: a set, two pair, or aces. The likelyhood of Phil Ivey having one of those hands is somewhere in the range of 2%. In tournaments and normal short and medium stack play, calling an all in on the flop with kings is almost always correct. But once the stacks go well over 150 big blinds - and in this case they are playing with 500+ big blinds - the values of starting hands normalize and calling off your entire stack with one pair is almost never correct - unless that pair happens to be aces and the preflop action suggests you have your opponent drawing to two outs.
But Booth's play has another purpose besides simply getting Ivey to correctly fold, and winning a small pot. He is advertising that he is unpredictable, dangerous, reckless, and willing to gamble with you for every last penny in your wallet with just 4 outs to a gutshot straight draw. Let me tell you as cash game player, thats the last guy in the world you want at the table. You want to play against predictable opponents who play a narrow range of hands and make routine plays. Booth is telling Ivey - Im the craziest motherfucker at this table and dont you even think about playing back at me. Its a play that as I said before, has little short term value, but it establishes Booth's image as a fearless player, and within the metagame inside the game of poker, the monetary value of your opponents fearing you is unquantifiable.