Mass of aliens: 2 d% rolls, 46 and 55, normal range of 46 to 55 kg, or take the higher # and use +/-46%? That's a range of 30 to 80 kg, 66 to 176 #s, average of 121 #s.

Bilateral or radial symmetry? 60% chance bilateral, 44 is a yes. Bilateral evolved from 'fish'. That last is just a judgement call, crawled up into the mud with more that two pairs of legs? 36 under... 36%? Interesting. Yes. More than three pairs? 51 over 44%, so no, three pairs, a centauroid?