Wikia

Immolation Trap
Immolation Trap 30 seconds cooldown 9% of base mana Instant cast Place a fire trap that will burn the first enemy to approach for [RAP * 0.1 + X] Fire damage over 15 sec. Trap will exist for 1 min. Only one trap can be active at a time.
Usable by
Class	Hunter
Properties
Type	Offensive
School	Fire
Cooldown	30 seconds
Talents
Talented	No
Other information
Ranks	8
Related debuff
Magic Immolation Trap Effect {X/5} Fire damage every 3 seconds. Duration: 15 seconds

Rank Table

Rank	Level	Mana Cost	Damage	Training Cost
1	16	13% of base mana	105	18
2	26	13% of base mana	215	70
3	36	13% of base mana	340	1 40
4	46	13% of base mana	510	2 80
5	56	13% of base mana	690	4 60
6	65	9% of base mana	985	11
7	72	9% of base mana	1540	30
8	78	9% of base mana	1885	30

Trap Mastery (Survival Talent): Increases periodic damage by 10%/20%/30%.
Resourcefulness (Survival Talent): Reduces the mana cost of all traps and melee abilities by 20%/40%/60% and reduces the cooldown of all traps by 2/4/6 sec.

Immolation Trap is the trap you will most often use while grinding and solo-ing. The standard operating procedure is to lay the trap just outside of the mob's aggro radius and then back up to maximum range. Timed correctly, when you pull the mob it will encounter your pet just after it hits the trap.
Immolation Traps are also best used for boss fights in instances, as generally, the more DoTs on a boss the better.
Immolation Traps are also useful when fighting Elementals, as elementals generally have heavy armor and are immune to stings.
While overshadowed by Explosive Trap in long-term/multi-target damage, against single moving targets this can be slightly better.

Patch 3.0.8 (2009-01-20): Trap Mastery now only increases periodic damage done by Immolation Trap and Explosive Trap

Previously increased all damage.

Patch 1.7.0 (13-Sep-2005): Fixed a bug where lower level versions of Immolation Trap were being resisted more than they should be.