The Leech is a passive item in The Binding of Isaac: Rebirth (TBOIR)
When you pick Leech up, you get a Familiar that crawls and follows Isaac around
If the leech gets close to a monster, it will attack the monster until killing it.
Upon killing the monster, Isaac will gain half a heart of health. The leech will then attack another enemy if there is one close by, otherwise it will return to Isaac
Character has a leech crawling and following him around:
- The Leech kills by sucking blood out of enemies and this can be slow especially against more powerful enemies
- If you are in a room with a lot of weak enemies (such as flies) and are low on health, don't kill them - instead approach them with the leech. The leech will charge all the enemies and kill them one by one, replenishing all your health.