A Jawa Force implode was an action of great desperation which can be performed by Jawas with a Force connection. It caused the Jawa to implode, killing itself and all those attacking it. Any Jawa using Jawa Force implode was certain to come back as a Force ghost soon after.
It is uncertain whether species other than Jawas could perform Force implosions, and whether there was a non-fatal way of performing one.