Ruby and Sam use [[Devil's trap (symbol)|Devil's trap]] to restrain a possessed man while Sam uses his power to exorcise the demon. At this point Dean enters, and discovers what Sam is up to.
[[Image:Devils Trap in Metamorphosis.jpg|250px|left|
frame|The demon about to be exorcised]]
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==[[4.16 On The Head Of A Pin]]==
[[Castiel]] binds [[Alistair]] to a [[Devil's trap (symbol)|Devil's trap]] which he describes as being old [[Enochian]]. So that [[Alastair]] will kill [[Dean]] and escape, [[Uriel]] causes a water leak which drips onto and erases part of the trap, letting [[Alastair]] go free.