The entosis mechanic was added to the game by CCP to generate events around which PvP content is generated.
The Entosis Link
This is a high slot module that can be fitted to any ship with the exception of interceptors and some larger ships are penalized by the entosis link cycle time being lengthened. Capital Ships take five times longer to complete an entosis cycle.
The entosis link requires fuel. It runs on Strontium Clathrates, commonly referred to as 'Stront'. Each cycle of the entosis link runs a two or five minute timer dependent on if it is a Tech I or Tech II module. Each cycle consumes 1 Stront per cycle.
While the entosis link is active your ship will be unable to warp, cloak or receive remote assistance such as repairs and capacitor boosts. All your local modules such as weapons, hardeners, webs and scrams work as normal and you can deploy drones. However your speed can not be greater than 4,000 ms.
Valid entosis targets are limited to Outposts and outpost modules, TCU's and IHUBS and can only be used during the vulnerability timer of the structure. Once the structure exits reinforcement, the entosis link can then be used on command nodes, which is the basic content driver of the Entosis Mechanic.
The Tech I Link has a cycle time of five minutes and a maximum range of 25km and is relatively easy to fit with fitting requirements of 10 power grid and 1 CPU. Each cycle time lasts 5 minutes.
The Tech II Link has a cycle time of two minutes and a maximum range of 250km and is more difficult to fit with fitting requirements of 100 power grid and 10 CPU. Each cycle time lasts 2 minutes. Due to its' expense and fitting requirements it is typically fitted on Cruiser class ships, often Heavy Assault Cruisers or Combat Recon ships.
Screen shot of a command node being entosised.