Freeze (凍結 Tōketsu) is a mechanic that primarily appears on blue cards. It first appeared in WX-01 Served Selector. Freeze is a state that affects SIGNI or, more rarely, LRIGs, preventing them from upping during their owner's next up phase.
If a frozen SIGNI or LRIG is in the up state, it can still attack and use abilities as normal.
If a LRIG is downed during the grow phase due to having been previously frozen, when a player attempts to grow onto that LRIG, the LRIG being grown into enters the field downed.
For the purposes of cards that check for frozen SIGNI, such as ICE BREAK, the frozen state lasts until the up phase in which the SIGNI is supposed to up.