You can drop her, and then when you need, monstrous her up
If that wasn't enough, if you cast a spell which is multiple of these MTG colors, you get each of the abilities that share a color with the card cast
I wish it had more colors to have more weird counters from something like blue or green (the other colors in this precon deck, ahem), but it's pretty cool
With Elven Council being only 2 colours, it makes Mana fixing a lot more easier, solving a potential bugbear for new players
Some instants can be used to counter another spells, to destroy a creature, give the power and toughness of a creature a boost, ect
This situation doesnt come up that often though, which is why I valuable Night Whispers flexible mana cost over Sign in Bloods ability to target other players