We'll See About That

A Stock Phrase that is typically uttered by the Big Bad after being told that the protagonist is there to stop them. This almost always leads directly to the Fight Scene. Typically used to show the arrogance of the Big Bad in thinking he can't be stopped by anyone. If he loses, expect him to have a Villainous Breakdown that invariably includes This Cannot Be!.

Alternatively, the hero will be saying this to the Big Bad, typically in response to the Big Bad's taunts that "You're too late to stop me", "I AM INVINCIBLE!!!!", "You Have no Chance to Survive Make Your Time", etc. Less patient heroes will say it while the Big Bad is still taunting them.

Examples of We'll See About That include:

Anime

Inuyasha

Kagome: You stinking toad.
Jaken: You stinking human.
Kagome: Oh yeah? Well, this human's gonna kick your...
Jaken: We'll see about that.

Bleach episode 157. While Chad is fighting Arrancar #107, the Arrancar tells him that if he continues fighting he'll die. Chad says "We'll see about that".

Comic Books

Subverted in Watchmen. Ozymandias executed his master plan before the heroes even arrived.

Film

Dillinger says this in Public Enemies, after being taunted that he'll never leave his jail cell until being removed for his execution.
The Secret Garden: Mary's reply in the 1987 movie when Martha says that Colin is going to "scream and scream until he brings the house down" is... you guessed it... "We'll see about that."
After Jafar usurps power, Aladdin says this and whips out the lamp... or not.

Video Games

World of Warcraft: In the Culling Of Stratholme there is a part of the dungeon where a Boss from the Infinite Dragonflight emerges to say he's there to stop Arthas from purging Stratholme. Arthas replies that nothing can stop him, in response the boss utters this phrase.
The G-Man says this in Half-life 2: Episode 1 when the vortigaunts free Gordon from his control.
Kingdom Hearts

Sora: My heart will stay with my friends. It'll never die!
Riku: Well, we'll just see about that!

Western Animation

In The Simpsons episode "Homer Badman", Homer delivers this line:

Homer: Like one time, they were having this race with the stupid old tiny bicycle with the big wheel in front, so I figure, "We'll see about that!" So I get this big chunk of cinderblock, and -- (cut short)

Said by Rainbow Dash in "A Dog and Pony Show" on My Little Pony Friendship Is Magic. Discord uses it on her in "The Return of Harmony, Part 1" after she declares that she'll always be loyal to Princess Celestia.