Glyph of Sacrifice

Glyph. For 15 seconds, your next spell casts instantly, but it takes an additional 30 seconds to recharge.

Glyph. (15 seconds.) Your next spell casts instantly. This spell takes an additional 30 seconds to recharge.

Acquisition

Bug.

While the skill description states the next spell casts instantly, the next spell actually casts in 1/4 second.

Can be used to cast hard resurrection spells such as Resurrection Chant quickly and with no threat of disruption.
Can be combined with Echo since the copied version of the skill will usually expire before a second use anyway.