This new ‘pyramid piece’ (Bricklink 22388)debuted in 2016, as part of the Nexo Knights range. It is available in a number of colors including the new ‘Flat silver’, Pearl Gold and trans orange. EDIT: Trans light green has also been spotted in the wild (in one of the new Elves sets, March 2016).
It is primarily used as a decorative component( sets 70312,70313, 70314 and others). However 5 of these pieces around a Modified 1×1 block with 4 x side studs (Travis brick) with trans-red studs are used to form the business end of Ultimate Macy’s mace (70331)