Goblin Smuggler

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}: Another target creature with power 2 or less can't be blocked this turn.

Foundations

Foundations Jumpstart

"I am but a humble traveler. I have no taste for sneakery nor thiefiness."

Core Set 2020

If the target creature's power is greater than 2 as the activated ability tries to resolve, the ability doesn't resolve. However, if instead the creature's power is raised above 2 after the ability resolves, it still can't be blocked that turn.