({2} magic symbol) ({U} magic symbol) without using ({R} magic symbol) available.
Steps
Cast Glasspool Mimic by paying ({2} magic symbol) ({U} magic symbol) , without using ({R} magic symbol) , having it enter the battlefield as a copy of Crypt Champion.
Glasspool Mimic enters the battlefield, triggering its first and second abilities.
Resolve the second Glasspool Mimic trigger, causing you to sacrifice it.
Resolve the first Glasspool Mimic trigger, returning Glasspool Mimic from your graveyard to the battlefield as a copy of Crypt Champion.