Fetched: 2026-10-31. developer.valvesoftware.com blocks automated fetches with a bot check, so its passages below come from search-result excerpts of the pages named.
https://theportalwiki.com/wiki/Gels : Repulsion "a light blue substance"; Propulsion "a light orange substance"; Conversion "white substance"; Adhesion "made purple as a placeholder".
https://combineoverwiki.net/wiki/Aperture_Science_Sentry_Turret : "a single red eye"; searching: "scan back and forth across the area with the laser"; back to sleep after three seconds; knocked over: "fire[s] frantically in all directions before permanently deactivating".
https://combineoverwiki.net/wiki/Weighted_Companion_Cube : the Portal 2 Companion Cube "has a heart on each face of the Cube and emit[s] a pink light"; storage cubes "have a circular blue light on each side, and when left on a button it changes to a yellow light."