He hated the Ring and loved it, as he hated and loved himself.

Gollum, Obsessed Stalker

Skulk (This creature can't be blocked by creatures with greater power.)
At the beginning of your end step, each opponent dealt combat damage this game by a creature named Gollum, Obsessed Stalker loses life equal to the amount of life you gained this turn.

Tales of Middle-earth Commander

Skulk
At the beginning of your end step, each opponent dealt combat damage this game by a creature named Gollum, Obsessed Stalker loses life equal to the amount of life you gained this turn.

Gollum, Obsessed Stalker's last ability counts players who were dealt combat damage by any creature named Gollum, Obsessed Stalker. It doesn't matter who controlled those creatures.

Gollum, Obsessed Stalker's last ability counts the total amount of life you gained without taking into account any life you lost during that turn. For example, if you gained 3 life and lost 3 life earlier in the turn, each opponent dealt combat damage this game by a creature named Gollum, Obsessed Stalker loses 3 life.