This is a BB(6) Cryptid found by @mxdys and shared on Discord on 20 Aug 2024.
Analysis by @mxdys
1RB1LD_1RC1RE_0LA1LB_0LD1LC_1RF0RA_---0RC
start: (0,0)
(3x+0,y) --> (4x+4,y+1)
(3x+1,y+1) --> (4x+5,y+2)
(3x+2,y) --> (4x+8,max(0,y-1))
(3x+1,0) --> halt
(x,y) := 0^inf 110 <B 11011 01^x 011^y 0^inf