March of the Machines

A noncreature permanent that turns into a creature is subject to the "summoning sickness" rule: It can only attack, and its tap abilities can only be activated, if its controller has continuously controlled that permanent since the beginning of their most recent turn.

If a noncreature artifact becomes an artifact creature this way and then another effect animates it, the new effect overrides March of the Machines's effect. For example, Chimeric Staff is a 4/4 creature while March of the Machines is on the battlefield. If you activate Chimeric Staff's ability and choose X = 5, Chimeric Staff will be a 5/5 artifact creature for the rest of the turn.

Each artifact land has a mana value of 0. March of the Machines makes them 0/0 creatures, which are put into the graveyard as a state-based action.