Is this bluff genius or insane?

[TripleJ]

My opponent made a bluff at me at the wrong time, but I couldn't help thinking that it would have worked if I had any other holding. BTW did I miss out on some value here? (Disregard what villian turned out to have.) Sorry for posting results but they're needed to evaluate the hand from both points of view.

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.10/$0.25
9 players
Converter

Stack sizes:
UTG: $31.30
UTG+1: $29
MP1: $23.15
MP2: $19.75
MP3: $25.20
CO: $23.10
Button: $7.15
Hero: $48.50
BB: $28.05

Pre-flop: (9 players) Hero is SB with 4[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/diamond.gif[/img]
7 folds, Hero calls, BB checks.

Flop: 4[img]/images/graemlins/heart.gif[/img] 4[img]/images/graemlins/club.gif[/img] 9[img]/images/graemlins/club.gif[/img] ($0.5, 2 players)
Hero checks, BB checks.

Turn: K[img]/images/graemlins/heart.gif[/img] ($0.5, 2 players)
<font color="#cc0000">Hero bets $0.5</font>, <font color="#cc0000">BB raises to $1.5</font>, Hero calls.

River: 3[img]/images/graemlins/diamond.gif[/img] ($3.5, 2 players)
<font color="#cc0000">Hero bets $2.5</font>, <font color="#cc0000">BB raises to $7.25</font>, Hero calls.

Results in white:
Final pot: $18
<font color="#ffffff">Hero showed 4s 5d</font>
<font color="#ffffff">BB showed Ac 6s</font>

[Pokey]

In your situation, I bet the flop for $0.50. I'm VERY frequently betting the flop in this situation whether I've got a hand or nothing, so I see no reason not to do so when I've got a monster.

As played, I probably three-bet the turn with a pot-sized raise, fully intending to call down if I'm four-bet. My feeling is that there are now two very live draws, and I want them both to pay the maximum penalty. It's always possible that the case 4 is slowplaying, but with the K on the board I now have TONS of counterfeiting outs to a tie against even that hand.

As played, I have to smooth-call this river. My opponent has shown too much strength for me to not be at least a little afraid, and I think his calling range of my three-bet makes it a -EV move for me.

From his perspective, he'd have had a better chance betting the flop. Your play stinks of a slowplayed hand or a K, and he should know that he's not pushing you off either of them. The flop was the time for him to make his move -- only five cards connect with that flop, so there's a good 85% chance you don't have a hand. A solid (pot-sized) bet should drive you away the vast majority of the time, and even a min-bet gets the job done quite often against an unknown. At the turn I don't mind his raise, but at the river his raise is pure spew.

[Chris_ca]

Doesn't make much sense to me. He raises the turn and you call. Then when you bet the river, essentially saying, "I'm not afraid of you holding a 4", he raises again on a blank.

Also, 3-bet the turn, although in this case just calling induced a nice bluff.

[Big Poppa Smurf]

yeah your turn-river line is really weird, either 3bet the turn or checkraise the river