Why is this a draw?

I was playing horde and my opponent move his last pawn forward looking for a draw putting his pawn directly in front of mine. They were one square away and I thought I was gonna be ok because if he pushes I can capture on my next move, but he pushed the pawn and in my last move were I clearly can take the pawn, he draw the game.

He just pushed the pawn and the game ended in a draw 

where is the white King?

This is a different chess variant, the game started like this:

to win the game you need to eat them all. 

In this supposed stalemate if he pushes the pawn and I move something else rather then take it, he won't have legal moves. This is why I don't understand, because he pushed and then in my turn he was stalemated not giving me chance to take it.

Oh I understand now ...Like giveaway! A type of Loser game! By the way I like Loser chess but there is no here in chess.com.

This is complicated,  you need to get an open file to get through and attack them from behind and to do that you need take the most of the pawns in the exchanges, like sacrifice a knight for two pawns, a bishop for two pawns and lastly the rooks when you are sure You are gonna get through.