Timeworn Sentry

Defender, Shroud
If an opponent controls 2 more creatures than
you by your third turn, you may cast Timeworn
Sentry for {2}{g}. If you do, it enters the
battlefield with "{t}: Timeworn Sentry fights
target creature."
When Timeworn Sentry enters the battlefield, if
you cast it for {3}{g}{g}{g} it loses Defender and
gains Haste and Trample.