Dr. Martin Brenner

When Dr. Martin Brenner enters the
battlefield, create four 1/1 colorless Experiment
Child artifact creature tokens.
Whenever Dr. Martin Brenner attacks, you may
tap X untapped Experiment Child you control.
If you do, Dr. Martin Brenner gets +X/+0 until
end of turn and deals X damage to the
player or planeswalker he's attacking.
What... have you done?"