You have a card in hand with kicker or multikicker.
You have a way to cause a creature to leave the battlefield.
({G} magic symbol) ({G} magic symbol) ({G} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) plus enough mana to cast the kicker spell kicked available.
Steps
Cast Body of Research by paying ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) , creating a 0/0 Fractal creature token, then putting a number of +1/+1 counters on it equal to your deck size.
Cause the Fractal to leave the battlefield.
The Ozolith's first ability triggers, putting a number of +1/+1 counters on The Ozolith equal to the number the Fractal had.
At the beginning of your combat phase, The Ozolith's second ability triggers, moving all counters from it onto Hallar.
Cast any kicker or multikicker spell with kicker by paying its mana cost plus its kicker cost.
Hallar triggers, putting a +1/+1 counter on itself, then dealing damage equal to the number of +1/+1 counters on it to each opponent.