[NegranuFan]

what were your stacks like relative to the blinds?

call out of boredom, maybe to switch things up? Where you went wrong was not raising the flop. It is irrelevent what he calls before the flop because he figures to win your whole stack if he hits and lose nothign more if he misses.

double the BB bet by him is almost appologetic, but again he might have thought that it might be small enough to give him odds( again I counted 9-1), and big enough to act as a blocking bet, causing you to slowplay your hand, represent KK, or QQ perhaps (I figure he felt that any heart was good, in which case, his bet worked perfectly). Either way he is conceding that he is weak and you should bloop him back hard.

What would you have done if he bet the pot into you on the flop?
1/2 pot?
All-In?