A very large pokemon that looks like a trex but made of crystals, unlike most pokemon this can come in ANY element and has a colour corresponding e.g blue = water, red = fire, light blue = ice, and very rarely you find rainbow Crystal Tyranno's, bieng part of ALL types, it has no weaknesses and minor strength boosts (so if you have a grass crystal, its effectiveness vs water would be 80, against all others it will be 50, and against fire it would be 30, and the rainbow Crystal Tyranno's effectivity vs ALL is 60) so against pokemon like this there really is strategys other than hoping you have the right pokemon.

Note: For diffrent areas they will have slightly darker/lighter colours so its not a solid colour, the teeth/spikes would be a darker colour excluding rainbow Tyrannos.