elephants have the biggest brain out of any mammal
brehs are smarter than us
I know you're likely joking but I feel like giving a pointless educational post so--this isn't 100 percent true.
While elephants are likely the smartest non-human land mammals, brain size isn't the only factor. It's a combination of brain size (eg: amount of neurons), brain/body mass ratio and the amount of grooves in the brain.
Humans have a brain body mass ratio of 1:40, which is amongst the best in the world. Elephants are 1:560. So an elephant brain is bigger than a human brain, but takes up far less space in their total mass than a humans does. Because our brains take up so much space in our mass, we need to expend more energy to keep it running. Which is why we're so smart. There are a select few animals with even better brain/body ratios than humans, such as ants. But since they're so small so are their brains. They simply don't have enough neurons to compete. We're talking 250k neurons vs 100billion. If you could upscale an ant to the size of a human though, it'd be interesting to see.
The amount of grooves in the brain also matter. This is a koala's brain:
Note how smooth it is. That, in combination with the terrible brain/body mass ratio, makes koalas amongst the dumbest animals in the world.