Flee the Mad beholder!
Each person must complete a skill challenge: 4 successes before 4 failures. That means you have to make four skill rolls on the Primary Skills list below, before you fail four rolls. The DC starts at DC 12 and increases by +2 every time you use the same skill more than once. A failure on one of these checks causes you to be attacked by the beholder's eye rays. When you succeed you've managed to slip away from the monster, you can still aid your companions (but you can not take the continue on to Thrace action).
If you fail you fall behind and the beholder catches up to you. This is bad.
You can assist others by using the Secondary skills: success gives the person +2, failure gives them -2 on their next Primary roll. Every time you try to use the same skill to help the same person, the DC rises by two.
Skill checks are a standard actions. If for some reason you do not use your move action to flee during your turn you get a -2 penalty to your next primary skill check and MUST use the next attempt to flee or you automatically gain one failure.
Primary skills (start at DC 12): acrobatics, athletics, dungeoneering, endurance, nature, stealth. DC goes up by 2 every time the same skill is used.
Secondary skills (start at DC 12): arcana, insight, nature, history, perception.
Teleport 5 or more squares: 1 automatic success for the teleported party member.
Ranged Attack: Reduce the attack roll of the next eye-ray by 2 on success or grant a single ally member a +2 bonus to their next action on success. On failure you become distracted and wander into an area of magical hazards (can not attack while in a hazardous area).
Continue on to Thrace: While you’re performing the skill challenge, you can try and guide the party towards your final destination of Thrace (if you're not in an area of magical hazards). Make a nature check, DC 17. On success you help redirect the wayward party towards their final destination. If you fail you are attacked by the eye rays or you wander into an area of magical hazards (50/50 chance) as you hesitate to try and pick out your way through the waste. No successes here results in the group being hopelessly lost. One means you know roughly where you are, but loose a day of travel. Two keeps you on course. Three and you find the best path to escape and advance, granting all allies a +2 bonus to any remaining primary checks.
Special: If the beholder acts last everyone starts with one success. If the beholder gets a surprise round everyone unaware starts with one failure, if any players get a surprise round they start with one success.
Eye Rays: +19 vs. NAD, 1d8+5 damage + some other effect (depending on the ray).
1) Numbing Cold (cold, fort) - You are slowed (save, endurance or heal[DC 15], others can heal you as well, ends). Your successes do not count until you are no longer slowed.
2) Telekentic Blast (force, reflex, attacks anyone who aided you last turn as well) - you are hurled randomly (1d8)
8: away, you gain 1 success
1-2: backward, you gain 1 failure
3) Fear (psychic/fear, will) - you are shaken (save ends): -2 to defenses and any non-primary skill checks, +1 to primary skill checks.
4) Petrification (fort) - 1 automatic failure, no damage.
5) Venom (poison, fort) - You loose a healing surge.
6) Domination (psychic, will) - You are dominated for 1 round, during which you attempt to hinder an ally with a secondary check and do not flee (success is a -2 to their next check, failure means nothing).
7) Stone to Mud (auto hit, no damage) - You drop neck deep into a pool of sticky mud. You can take no action but try to escape (Athletics DC 12, others can pull you free as well). After you escape you are coated in thick mud, giving you a -2 to all Str/Dex/Con checks and attacks (save ends).
8) Barrage - The beholder makes two ray attacks, against you and one other ally (reroll any 8s)
Anti-Magic Ray (recharge 6): An an interrupt the beholder makes an opposed roll (+10) with the person using the power. On success the power is negated. Utility powers use the most relevant attack bonus, racial powers use your highest stat bonus +1/2 level +2.
Magical Hazards: Random trap, level 1+1d4 (DMG 88), reflavored as a magical hazard. Arcana is an added skill that can be used for most interactions.