Avengers V01 # 28

Henry Pym calls the Avengers, telling them that he is Giant-Man and that the Wasp is missing. The Wasp has been captured by the Collector and the Beetle. The Scarlet Witch presents Hank with a new costume she'd just happened to have been sewing in the hopes that he might return to the team. Along with the new costume, he renames himself Goliath.

The Avengers enter the Collector's lair and get seperated and captured but Goliath escapes and frees the other Avengers. They rescue the Wasp and force the Collector to escape with the Beetle using a time machine.

Afterwards however, when Goliath tries to shrink down to his normal size, he collapses and faints at 10 feet tall.

Avengers V01 # 28