Electromagnet
Unnaturally attractive
<&recipe>An Electromagnet is simply a big coil of wire wound around a ferromagnetic core which creates a magnetic field when provided with electric current.
This field attracts nearby items to the magnet, making it ideal for collecting the spoils of a (mob-)farm.<br>
The magnet runs continuously while it is being supplied with power, but can be disabled with a redstone signal. This behavior can be inverted by sneaking and rightclicking it with an Engineer's Screwdriver.