Stars 2 table 10+1 SnG, chip lead, 6 left, KK

[Marc H]

Blinds 200/400

Seat 1: HERO (7870 in chips)
Seat 3: VILLAIN (7835 in chips)
Seat 4: mwl pool (2225 in chips)
Seat 5: 8lackAce (1635 in chips)
Seat 6: emefge (4355 in chips)
Seat 9: mechan1c (3080 in chips)
HERO: posts the ante 25
VILLAIN: posts the ante 25
mwl pool: posts the ante 25
8lackAce: posts the ante 25
emefge: posts the ante 25
mechan1c: posts the ante 25
mechan1c: posts small blind 200
HERO: posts big blind 400
*** HOLE CARDS ***
Dealt to HERO [Kc Kh]
VILLAIN: raises 400 to 800
mwl pool: folds
8lackAce: folds
emefge: folds
mechan1c: folds
HERO?

What's my smartest choice here?
Push? Reraise? Flat call? (Fold into the money???)