Yep, red
Naturally, the destruction of something so warm and innocent like the Shire appears to be, and the corruption of many hobbits, is something that I wanted to show in detail in Magics adaptation of the books
Rampant Frogantua's second ability counts every player who has lost, no matter how the player lost the game: due to a state-based action (having 0 or less life, trying to draw a card from an empty library, having 10 or more poison counters), because of a spell or effect that states they lose the game, because your awesome might has left them with no choice other than concession, or for any other reason
Tapping doesnt always matter, but you do always get Scry 1 draw a card, and when tapping does matter or even better when you have a tap payoff in play this gets significantly better
At 8 mana and with such heavy black requirements he is rarely cast instead preferring to be cheated into play but with cards like Dark Ritual and Lake of the Dead and 8 mana card is at its second most realistic for being cast in black