Land

: Add

.

: This land becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.

,

: Target attacking Assembly-Worker gets +2/+2 until end of turn.
If Mishra's Foundry becomes a creature and you haven't controlled it continuously since the beginning of your most recent turn, you won't be able to activate its first or last abilities, and it won't be able to attack (unless it somehow gains haste).