Lost? Wait for the next special and find it in the specials order. Then count Basic 1, Null, Basic 2, and the next special is the one after it.
What counts as a basic: anything fired from Olm's head: magic, ranged, coloured spheres, burn, fire wall, acid. Not basics: Crystal Burst, Lightning and Swap (and the healing hand later).
You are on the mage side (left) on long range, hitting the mage hand. A thrall helps, because splashes break the skip. Your melee guy stays on the melee side (right) and also attacks the mage hand from range. He must never step past his marked tile, or the head looks at the centre.
Olm's head has three positions: left, middle and right. It only turns when Olm acts (every 4 ticks), it turns toward the side with the most players, and if nobody is where it's looking, it turns and loses that action. On the null, Olm doesn't attack. Its head swings toward the claw that took the most damage in the last 4 ticks. You're both hitting the mage hand, so the head comes to your side every cycle. That's why Basic 2 is yours.
You only need 3 tiles at the head: the tile left of the head, the centre, and the tile right of the head (the pack's two head tiles plus the centre). Tank Basic 2 on the centre tile. Then step one tile right, out of the mage-side view. When the special is due, Olm sees nobody on your side, turns its head right, and loses the special. As soon as the head turns, run back LEFT.
Tank 2 basics. On the 2nd, the head must be turned fully to your side. Then step right, and go back left when the head turns. The skip is set. Shortcut: if a special lands while the head faces the melee side, run left and it's set. If a special lands while the head faces your side, tank one, step right, and it's set.
Click as soon as you see the head start to move; the turn has already happened. Your click takes effect on the next tick, so click one tick early. Tank Basic 2 on the middle tile so a fire wall can't trap you.
Running right as soon as the head turns to you. You must tank Basic 2 in the middle first. If you leave early, Olm loses a basic instead and the special still comes.
You start seeing specials again (Crystal Burst, Swap, Lightning). Don't panic: look at which side the special happened on, then set it again (step 4).
Hitting the melee hand harder than you hit the mage hand, or stepping past his tile, makes the head go the wrong way on the null.
Olm faces the middle if players bunch up near the centre, if your melee guy steps past his tile, or if the claws only took zeros before the null (splashes, no thrall). For your Basic 2 the head must be turned fully to your side. If it looks at the middle, tank that attack and go back to your side to keep it set.
Chambers of Xeric Additions (Buchus): Olm side highlight, claw HP overlay, phase panel, and a "Replace Olm Orbs" option. Visual Metronome set to a 4-tick cycle. Tile Packs: "CoX Olm standard" (the yellow tiles in the trainer).
Sources: Synq, The EASIEST Mage Skipping Guide (Duo Olm) · Qevon, Mage Skip for Dummies · Daep, Melee & Mage Skip guide · OSRS Wiki
A duo has 4 phases: three claw phases, then the head. Olm comes up on the other side of the room each time.
Tell: first rise. Chat: "The Great Olm rises with the power of acid / flame / crystal."
Set: it starts melee-set because everyone hammers the melee hand. Spec until it cripples, go left, tank Basic 1 and keep the head left through the null, tank Basic 2, then run right; back left when the head turns.
Tell: second rise, a different power, Olm on the other wall.
Set: almost the same as phase 1. Run to your tiles first; you have time for one hit before going left. Spec then run straight to the mage side often sets it instantly.
Tell: head glows green, all powers, an infinity symbol on the melee hand (Heal special), lightning has an extra bolt.
Set: melee hand no longer clenches. Keep skipping; Heal comes after Portals, skip it the same way. Dodge Basic 1 if it's a fire wall. Both claws low, melee hand first.
Tell: "The Great Olm is giving its all. This is its final stand." No claws, crystals keep falling, blue Life Siphon tiles.
Do: kill the head with ranged from the 3rd row. Each of you tanks one basic. Stand on a blue tile for Life Siphon.
• Whoever tanks Basic 2 is the one skipping.
• Tanked two basics in a row? It's set for you.
• Melee hand cripples while the head looks away from you: it's set for you.
• A special lands while the head faces the melee side: run left, and it's set. A special lands on your side: tank one, step right, and it's set.
• You start seeing Crystal Burst, Lightning or Portals again: the skip broke. Tank two basics after that special, the second with the head fully on your side, then right, then left.
Sources: Synq, Qevon, Daep, r/2007scape and r/ironscape duo threads.
Each standard phase Olm rises with one power. In the 2nd-to-last phase it uses all three. A phase attack replaces about 1 in 3 of Olm's normal attacks (1 in 2 with all powers), so keep counting it as a basic.
Acid spray: green pools on the floor. Don't stand in them (3–6 damage a tick).
Acid drip: the target leaves a pool on every tile they walk off. Don't drip over your route tiles or onto your teammate.
"Burn with me!": the target burns for 5 every few ticks, and it spreads to anyone right next to them ("I will burn with you"). Keep a gap.
Fire wall: two walls trap the target. Walk out the open end, or put it out with water. The centre tile under the head can't be fire-walled.
Falling crystals: the target gets a red ring and crystals drop where they stand. Keep walking.
Crystal bombs: they explode after a few seconds. Be 5+ tiles away (15 damage at 4 tiles, more the closer you are).
Flashes a special icon = melee
Clenches into a fist = melee
"Right claw" on hover = mage
Green orb: MAGE
Crystal shard: RANGE
Olm's normal attacks. The coloured prayer orbs are on the right.
Red sphere: MELEE
Green sphere: RANGE
Purple sphere: MAGE
Tap a special above to start.
Tap Next step each time Olm acts (every 4 ticks). Anything fired from the head counts as a basic: magic, ranged, prayer orbs, burn, fire wall, acid. If the melee hand is crippled, there are no specials until it opens again.