Your time bubble warps arcane energies.
Prerequisite: 5th-level temporal tinker.
Benefit: Arcane spells and spell-like abilities function at either +1 or -1 caster level when cast within your time bubble. You choose whether to give a bonus or a penalty when you project your bubble, and cannot change this choice until the bubble expires. You receive this bonus or penalty, even when compressing your bubble.
Compression: For 1 round after you compress your time bubble, all other arcane casters who had been within it before it was compressed must make concentration checks or lose any spell they try to cast. The DC for this check is equal to 15 + your tinker level + your Intelligence modifier.