Weary Surgeon

Players can't sacrifice other creatures.
At the beginning of each upkeep, remove all infection counters from Weary Surgeon.
If another creature would die, put an infection counter on Weary Surgeon and regenerate that creature. When a counter is placed on Weary Surgeon this way, if it has three or more infection counters on it, sacrifice it. (You choose
the order to regenerate creatures if necessary.)