UNDOCUMENTED MECHANICS
30% of the life it steals is passed to you.
The minion's actual damage rises 55% above the base attack shown per skill level.
25% of the life you recover is passed to the golem.
Each level also gives golems +5% life — the in-game synergy list does not mention it.
Up to 1 at once.
"Converts damage to life" above follows a diminishing curve, not a flat gain per level; the other numbers in the same block do not: 86% at level 1, 112% at 5, 126% at 10, 138% at 20, 150% at the limit. Reaching the limit takes skill level 60, gear bonuses included, so the first few points are worth far more than the last ones.