Snake in the grass

The trouble is, I trusted him too much from the start. He has proved to be a snake in the grass.

Is he not here to throw us out—a thief, a spy, a snake in the grass?

He's a snake in the grass, I tell you guys / He may look dumb but that's just a disguise / He's a mastermind in the ways of espionage.

We were playing in Dallas, when that snake in the grass—Eight Ball, everyone called him—came up on my blind side …

Following her presidential defeat, [Ségolène] Royal stunned many observers by publicly dumping Socialist Party leader François Hollande – her companion and the father of her four children – and announcing she'd seek his post during the current election. To some, that made Royal the symbol of the strong, modern woman in politics; to others, it cast her as the classic snake in the grass.