Spells and spell like effects that target you are absorbed, their energy stored to power spells of your own. Absorption absorbs only ranged spells that have you as a target. Touch spells, effect spells, and area spells that affect you cannot be absorbed.

Once the spell is cast, you can absorb 1d4+6 spell levels (rolled secretly by the DM). The level of each spell you absorb is subtracted from the total. If a spell is only partially absorbed (because its level exceeds the number of levels remaining to be absorbed), divide the number of spell levels left unabsorbed by the original spell level. For spells that do damage, use the result to determine what fraction of damage you take. For spells that create effects, use the result as a percentage chance to be affected.

For example, you have three spell levels of absorption remaining and are struck by dominate person (cast as a 5th level spell). Absorption absorbs three levels of the spell, resulting in a 40% chance (2/5) that you will be affected normally. If affected, any saving throw the spell allows you still applies. Likewise, if you're struck by disintegrate (cast as a 6th level spell) with four levels of absorption remaining, two levels of the spell remain, and you take only 33% (2/6) of the damage you would normally take from the spell.