Ecco can gain temporary invincibility by singing to certain glyphs that is in certain levels (mostly the prehistoric levels). Invincibility Glyphs have the same appearance as any other Glyph, so Ecco does not know which ones will grant him this power. Ecco will not take any physical damage during this time, however he can still get crushed and killed by large objects, such as ice blocks, that cause instant death regardless. Ecco's oxygen and health bars will fully regenerate once the invincibility has worn off. A technique used by some players is to explore parts of the level they are unfamiliar with and subsequently return to the Invincibility Glyph, so as to not waste oxygen.